The distances look quite small tbh. I wouldn't worry about price per mile or complicating it that way.
Just put your hourly rate (your top rate hourly to factor in for vehicle wear and tear etc) X however many hours then add fuel (add in an extra £10 or so to cover for fuel cost rises)
So for example:
The full day will take 6 hours (including travel and cleaning the 5 sites)
Hourly rate £30 x 6 hours = £180.00
Then add fuel of £30
£180 + £30 = £210 total
Then break it down as a price per job so £210 divide by 5 sites = £42 per site.
This way if 1 site drops off you can easily deduct it from the price. Also if the figure of £42 looks too low once you have broke it down add a few quid on for good luck!
