I can tell you a few of the rates for people in business on their own:
for visiting clients to do quotes, £nil
For time spent taking waste materials to tip, £nil
For collecting tools and materials, £nil
For travelling time, £nil
For time spent pricing jobs and preparing quotes for clients who change their minds, £nil
For time taking vehicle to be serviced or repaired and waiting for it to be ready, £nil
For time preparing business accounts and tax returns, £nil
For time taking professional training and exams, £nil
For time off sick or injured, £nil
Holiday pay (per day), £nil