Data on gas meter installers?

[Student]

Hi, I'm doing non-commercial research on the supply chain of single phase electricity meter and low pressure gas meter installations. I have been looking for data from the big-6/MOPs but have not found a great deal. I was wondering if anyone here could help with my estimates:

Average travel time between meter sites: 15 minutes.
Average installation time for a combined dual fuel smart meter: 4 hrs for first attempt, 85 minutes after 20 installs, 40 minutes after 100 installs.
Meter installer pay: £15 - £30/hr.
Meter reader pay: £6 - £12/hr.
Number of dual fuel meters installed per day: 8.

I hope they're in the right ballpark, and thanks in advance for any help with my (naive) guesses... Apologies if you feel this is not the right place for a question but I've had no luck with the AMO, etc.