Key 2 — Past customers forgot you existed

It is not that past customers were unhappy. It is that a boiler serviced four years ago has since been serviced by whoever posted a card through the door, and the customer feels no disloyalty about it, because as far as they can tell the original firm stopped existing. It cannot be assumed that customers keep a plumber in mind. They keep one in a drawer, and the drawer is not searched — a phone is.

There is a structural reason the list sits unused. Construction is the least digitally adopting major sector in the UK: 58% of construction SME employers use digital tools to sell or manage the business, against 69% across all sectors.¹ The record exists — it has to, for the invoice — but it lives in an accounting tool never asked to do anything except add up. So the business spends its energy on strangers while the people most likely to say yes are never asked.

This is the Key where owners get nervous, and the rule is simpler than the nervousness. Under PECR and UK GDPR you may contact your own existing customers about similar goods and services you have already provided them — the soft opt-in — provided you collected the details in the course of a sale, every message gives an easy way to opt out, and you honour it immediately. That covers reminding a customer whose boiler you fitted that it is due a service.

What it does not cover is buying a list, texting people who have never been customers, or messaging about something unrelated to the work you did. Cold texting is not a grey area; it is the thing the rules exist to stop. Keep a record of where each contact came from, keep the opt-out on every message, and act on it the same day.

• Whether a usable customer list exists at all, and where it actually lives.
• How many past customers there are, and how many have equipment on file with a service interval attached.
• When any of them last heard from the business, and by what route.
• Whether the records show which job each contact came from, which is what makes the soft opt-in defensible.
• Whether opting out is possible and honoured.
• What the business would actually say to a past customer, and whether that message is worth receiving.

Brookfield Plumbing & Heating Ltd of Northwich is illustrative: The firm does not exist and the figures are constructed to reconcile. Eleven years of trading have left about 2,900 past customer addresses in its accounts package, none ever contacted for anything but an invoice. Of those, roughly 1,400 have a boiler on file — a make, a model and a date, recorded because an engineer needed it.

Those 1,400 are the list: Every one owns an appliance that should be serviced annually, in a house Brookfield has been inside.

Now the conditional, and it is a conditional: If Brookfield sent those 1,400 a single annual service reminder, and if 6% of them booked, that would be 84 services. At its £95 service price that would be £7,980 in a year, from customers it already has, with no advertising spent. It would also put an engineer inside 84 houses with ageing boilers, which is where boiler installs at £3,100 are actually found. None of that is a promise or a measured rate — it is arithmetic on a stated assumption, shown so an owner can substitute his own. The point does not depend on the 6% being right; at any take-up at all, the cost of asking is a text message.

The list stops being an accident. Every completed job adds a customer with the job type, the equipment and the date attached, so that in twelve months the business knows who is due. One message a year goes to each of them, timed to their own anniversary rather than to a campaign — “Your boiler was serviced last October, would you like it booked in?” — from the firm they already know, with an obvious way to say no. Not a newsletter. One useful, expected, specific reminder.

The owner can name, at any point, how many past customers he has, how many are due something this month, and when each last heard from him. The measure of success is that work arrives without anybody having found a new customer.

Export the customer list from your accounts package to a spreadsheet and count the rows. That number is usually the surprise. Then sort by the date of the last job, and from everyone you have not seen for eighteen months pick ten with a boiler you fitted. Send them ten individual messages — not a mailshot. Whatever comes back is the take-up rate for your own business, which is worth more than any figure on this page.

Knight Li Group, a UK consultancy for trades and small businesses, checks the list, the records and the permission basis with you as part of its free audit. You keep the count and the findings whether or not you go any further.