Can I throw a bucket of cold water on some of this ?
I recently was involved in helping out when 1 consumer unit was changed. It was to comply with securing an EICR certficate as the house was rented. This was in a victorian five bedroom, four bathroom, three storey townhouse (in the same street some of those bedrooms would be studio flats,or the same house would be in 3 /4 flats so it was a big house ). The original test and report of recommended works was by 1 electrician and took 2 - 3 hours. He charged around 300 for that. He then returned, PLUS apprentice, they worked a near 10 hour day and the bill was just over 1000. I know it is expensive, but it was Plimlico Plumbers, so yes it was going to be expensive, but they did a thoroughly professional job ( as you would hope for that sort of money ). But it was all contained in 1 consumer unit.
This job involves 5 consumer units, and in outbuildings ? Either it's a " Country Pile " in Wiltshire with stables, horses, paddocks, ballrooom .... or 5 tiny studio flats in an original 3 bed terraced house in Southall with multiple " granny flats " in the back garden.
This guy quoted 8 days, and gave a price based on 8 days. So that is the price for the job, starting on 1st September, ending on 8th September. Did he define what a " day " was ? Some trades consider a day 12 hours, some lucky BDs consider a day 5 hours. Regardless, you have a start date, a finish date and a price. Some will consider that days are " evened out ", by popping in for an hour one day, they doing a 12 hour shift on another. If he takes the amount of "days" he stated and charged you the price he quoted, then really, your agreement stands, it's not up to anyone to pick apart how he worked on those days, fast or slow, or how many tea breaks he took. 8 days, X price, job done.
The issue is there is an unauthorised visitor. You went into this with an expectation. Did you actually say I don't want anyone but you on my property ? I would personally grasp the nettle, state your expectation was that you expected only him on your property, you have a camera ( in all this talk about filming and law, surely there must be some relating to the fact that he will be filmed ), you have evidence of a visitor and you need explanations.
The blanket and pillow could be because if the job is that Wiltshire country pile barn or stables they are cobbled and unheated. She, whoever she is, could be just keeping him company, nattering and making tea. 4 hours is a long time for just, well, whatever.
Regardless, he didn't tell you he was having visitors, should have been honest, so he is in the wrong, and has acted unprofessionally, and he has to be held account and reprimanded for that. But iif the job completes on the day agreed, to the standard agreed, to the price agreed, that was the deal.
He may well be being unprofessional, bringing secret visitors into your home but all this stuff about telling his wife is straying into the personal. Even if he was shagging in your outhouse. Even if it was, you could have every right to penalise him financially, frankly sack him or withhold payment, but I don'think it is anyone's place to cross the the line from professional to personal.