Take the deposit by card or pay by bank so the money is with you straight away, and get the direct debit mandate signed in the same conversation. Before you collect the balance, tell your customer the exact amount and date in advance. If the balance changes, the mandate still stands; you just give fresh notice of the new figure.
In this article
The short version
- Take the deposit by card or pay by bank so it arrives straight away.
- Get the mandate signed in the same conversation as the deposit.
- Give notice of the exact balance amount and date before collecting.
- A changed balance needs fresh notice, not a new mandate.
- If the collection fails, retry or send a payment link.
The order that works
There are two ways to sequence this, and one of them tends to cause trouble. If you take the deposit now and ask for the mandate later, you end up chasing a signature from a customer whose urgency has passed. You've committed to the work, the balance has nothing behind it, and you're back to invoicing and waiting.
It tends to go more smoothly if you get the mandate signed while your customer is paying the deposit, in the same sitting, while they're still keen to get started.
| Step | What happens | Who it depends on |
|---|---|---|
| Deposit taken | Card, Apple Pay, Google Pay or pay by bank, so the money arrives straight away | Your customer, once |
| Mandate signed | Your customer authorises you to collect from their account | Your customer, once |
| Notice of the balance | You tell them the exact amount and date | You |
| Balance collected | The collection goes through Bacs on the date you gave | You |
| Money received | A few working days after the collection date | The Bacs cycle |
These are two steps, one after the other: a payment now and a permission for later. On Adfin, your customer can pay the deposit from a payment link and then set up the mandate, so the balance collects itself. If you agree the work through a proposal, Adfin's integration with Socket gets the mandate signed alongside the proposal.
How to take the deposit
Direct debit is a poor fit for a deposit. A brand new mandate, a notice period and the three-day Bacs cycle put the money days away, and the point of a deposit is to have it before you start.
Card, Apple Pay, Google Pay and pay by bank all take a deposit in seconds. Pay by bank moves the money over Faster Payments and can't be reversed by a chargeback, while a card gives your customer chargeback rights they may want on a large advance.
It helps to put the deposit on its own invoice or line, so your ledger shows what's paid and what's left without any arithmetic. And check with your accountant how the deposit and balance should appear on your invoices, because when you invoice can affect your VAT.
How to collect the balance
A direct debit lets you collect varying amounts, but only once your customer has had advance notice of the amount and the date.
The Direct Debit Guarantee sets the default at ten working days before the collection, unless you've agreed something different with your customer. Many providers agree a shorter period as part of the mandate. Adfin, for example, notifies customers at least three working days before each collection.
Your notice has to state an exact amount and an exact date. A schedule that only promises the balance on completion doesn't do the job. And the notice period comes before the Bacs cycle, not alongside it, so plan backwards from when you need the money.
The simplest approach is one notice, sent at the start, for a set amount on a set date. Then submit the collection for that date. The money moves through Bacs and reaches you a few working days later, so the balance will show as paid a little after its due date even when nothing has gone wrong. Keep the deposit and the balance pointing at the same job, with a shared reference, so both reconcile against it.
If the balance changes or the collection fails
A change of scope or price doesn't mean a new mandate. Direct debit is designed for amounts that vary, so the authority your customer gave still stands. What you need is fresh notice of the new amount and date, in writing and in time.
If the change comes too late for your notice period, you have two straightforward options: collect the amount you gave notice of and the difference later, or agree a shorter notice with your customer in writing and collect the new figure. Collecting an amount that doesn't match your notice is something to avoid, because it's grounds for your customer's bank to refund them under the Direct Debit Guarantee and reclaim the money from you.
If the collection fails, the bank sends back a reason, such as insufficient funds, a closed account or a cancelled mandate. A failure for lack of funds is often a timing problem, and a retry a few days later can work. Adfin retries failed direct debits for free and then asks your customer to pay another way, and its collection agents can follow up over email, SMS or WhatsApp within rules you set.
Where the mandate has been cancelled, the balance is an ordinary unpaid invoice again. Send a payment link and ask your customer what's changed.
Common questions
Can I take a deposit by direct debit? You can, but it's rarely worth it. A new mandate, a notice period and the Bacs cycle put the money days away, so card or pay by bank suits a deposit better.
Do I need the mandate before I take the deposit? No, but getting both in the same conversation means you're not chasing a signature later.
How much notice do I need to give before collecting the balance? Ten working days by default under the Direct Debit Guarantee, or a shorter period if you've agreed one. Adfin notifies customers at least three working days before each collection.
What if the final balance is different from what I expected? The mandate still stands. Give your customer fresh notice of the new amount and date before you collect it.
When will the balance reach my account? A few working days after the collection date, because of the Bacs cycle. On Adfin, direct debits arrive within three working days of the collection date.
What happens if the balance collection fails? The bank tells you why. You can retry if it was a funding problem, or send a payment link if the mandate has been cancelled.
Sources
- Bacs - Direct Debit (accurate as of October 2026) https://www.bacs.co.uk/bacs-schemes/direct-debit/
- Direct Debit - The Direct Debit Guarantee (accurate as of October 2026) https://www.directdebit.co.uk/direct-debit-guarantee/
- Adfin - Next-generation direct debit (accurate as of October 2026) https://www.adfin.com/direct-debit-payments
- Adfin - Pricing (accurate as of October 2026) https://www.adfin.com/pricing
- Adfin - Socket integration (accurate as of October 2026) https://www.adfin.com/integrations/socket
