Testing and Inspection Income: The Line That Anchors the Multiple

The LineWhy a buyer reads testing income differently from project turnover

An installation invoice records something that happened. A fixed wire testing invoice, raised against a portfolio on a defined cycle, records something that is going to happen again. That is the whole distinction, and it is why the two lines are underwritten so differently even when they produce the same profit this year.

A buyer is not paying for last year. They are paying for a view of the next three, discounted for the risk that the view is wrong. Project turnover has to be won again from a standing start every quarter, and the person who has historically won it is usually the owner who is leaving. Periodic inspection work is scheduled, budgeted by the client and renewed with far less effort, which makes the same profit considerably more reliable.

The practical consequence is that the ratio matters more than the total. A business at three million turnover with a quarter of it recurring and a business at three million with half of it recurring are two different propositions, and the second one attracts a different kind of buyer as well as a different price.

An installation invoice records something that happened; a testing invoice raised against a portfolio on a defined cycle records something that is going to happen again.

The TestHow the testing book gets underwritten in diligence

The first question is whether it exists in writing. A schedule of clients with contract dates, renewal dates, notice periods and values is evidence. A list of customers you visit every year because you always have is a description of goodwill, and goodwill attached to habit is priced lower than goodwill attached to a signed agreement.

The second question is the shape of the book. A buyer will want three years of billing by client so they can see attrition, price movement and how much of the total sits with the largest handful of accounts. They will look at the cycle dates to see whether the revenue is genuinely spread or clustered in two months of the year, and they will check how much of each visit converts into remedial work, because the conversion rate is often worth more than the inspection fee itself.

The third question is margin, and it is the one owners answer least confidently. Recurring work is only an asset if it is profitable after the engineer, the vehicle, the software and the reporting time. Employer National Insurance rose to 15% from 6 April 2025, with the secondary threshold cut to £5,000, and a labour-heavy testing book feels that change directly. A buyer will model the margin after it rather than before.

The Weak PointsWhat takes the argument away

Four things do most of the damage. One client carrying too much of the book, so the buyer prices the possibility of losing it. Arrangements that were never written down, so nothing transfers cleanly. Relationships held personally by the owner, so the renewal depends on somebody who will not be there. Remedial work carried out cheaply to keep a client happy, so the reported margin is not the real one.

Each of those is fixable, and each takes longer than a sale process allows. Putting rolling arrangements onto written terms with renewal dates takes a full year to work through, because the terms can only change when the renewal comes round. Moving a client relationship from you to a contracts manager takes about as long, and it has to survive at least one difficult conversation before anybody believes it has moved. That is the argument for starting two years before you intend to sell rather than two months, and it is the argument this line of the profit and loss account makes better than any other.