The problem is cost, and it will vary from firm to firm, but no good asking each to different amount of work. Also speed, when I came to have mothers house rewired I realised it could not be done while she was living there. If rewiring with people living in the house there is a safety and a logistics problem, keeping a freezer powered for example.
I had the qualifications to DIY, but it was going to cost around £600 a week for mother in a care home, so cheaper to get a firm in who could do it all in a week. Most days two men, but Friday we had around six. If you need to leave the house while it is being rewired then speed needs to be considered, and although I would agree with
@winston1 that network and TV is not a basic sparks job, both my son and I have both trained in setting up a LAN and also both hold our RAE and have been trained how to build and install aerials so it does depend on who you go to, some may be able to do it all, which saves lifting floor boards twice. And means can be faster.
Some things will make a difference to price, and there is not a simple answer as to what is required, I for example have selected an all RCBO consumer unit, but cheap make, many use just two RCD's maybe however more expensive make. Some times there is no option, depends on supply type, I stipulated all sockets to be on a ring with mother's house with the whole idea of adding extra latter.
I also said trunking allowed in room corners and where there was already trunking for central heating, but any cables away from corners to be buried. And one wall was papered, agreed no sockets on that wall. It is easy to re-plaster a painted wall, but wall paper need stripping or you end up with a proud fill so can't strip paper in future without sanding walls.
Some sparks will make good, others expect you to get decorators after, so you need to decide what you want them to do. I did making good as could do that with mother home, but could not have floor boards up with mother home.