Looking at it more holistically:
let’s say that the contractor did have to travel, and it ended up being a half day job. That’d mean the contractor charges £1100 per day. Assuming they take 6 weeks holiday, + 2 weeks for Bank Holidays + other closures:
550 * 2 * 5 * 44 = £242000
I have no idea about electrical contracting. Is this a reasonable estimate for running a business? (I’ve ignored the parts cost, because they’re such a negligible amount of the total cost of the job)