If all that work is in one domestic property I would start with a site survey chargeable or free or Hybrid.  What I mean by Hybrid is charge your survey time lets say £400 for the day and if the customer does not want to proceed then that's all they pay.  If the customer accept your quote for work then that £400 can come of the quote price.  (other day rates are available). This will help with stopping people wasting your time or just using your quote to get someone else to do the job cheaper.

During survey you need to look at things like the age of house and if they use floor board or chipbord/plywood floors.  Labour time varies depending on flooring.  Eg some chipboard is glued and screwed which most of the time means it gets destroyed when you lift it up is large segments.  Also worth noting that there is a heigher risk of service penetration if you have to cut blind into a floor.  Loft and wall insulation are some other points to consider.  Some PIR insulation will cause plasticiser migration on PVC/PVC 2 core % CPC/Earth

I would also then advocate doing an EICR of the property before work commences as they may be some Gremlins in the installation.  EG. shared Neutrals which are not an issue on a CU from 40 years ago but it will upset a new RCBO board if the lights are separated by floors/zones/compartments.

Other caveats to consider is making good, again this can be labour intensive.  Eg PVA/SBR chase, Bond chase, 1 or 2 coats of filler, 2 coats of paint

With the above being said here are the key questions

How many hours a day do you work?

How many days/hours do you think the work will take?

Location in the UK and the travel time to site?

What is your profitable day rate?  Eg some people work for £200 per day or price match however what they need to do is work out there operation cost per year and then divide by 12 and then they can work out how many days a month they want to work and what profit % they want.  This then gives an accurate day rate.

Eg Sole trader could make profit on a day rate of £150 to £500.  However a small company with 10 employee may need a day rate of a minimum of £700 thus paying for admin staff and an office.

If all that work is in one domestic property I would start with a site survey chargeable or free or Hybrid.  What I mean by Hybrid is charge your survey time lets say £400 for the day and if the customer does not want to proceed then that's all they pay.  If the customer accept your quote for work then that £400 can come of the quote price.  (other day rates are available). This will help with stopping people wasting your time or just using your quote to get someone else to do the job cheaper.

During survey you need to look at things like the age of house and if they use floor board or chipbord/plywood floors.  Labour time varies depending on flooring.  Eg some chipboard is glued and screwed which most of the time means it gets destroyed when you lift it up is large segments.  Also worth noting that there is a heigher risk of service penetration if you have to cut blind into a floor.  Loft and wall insulation are some other points to consider.  Some PIR insulation will cause plasticiser migration on PVC/PVC 2 core % CPC/Earth

I would also then advocate doing an EICR of the property before work commences as they may be some Gremlins in the installation.  EG. shared Neutrals which are not an issue on a CU from 40 years ago but it will upset a new RCBO board if the lights are separated by floors/zones/compartments.

Other caveats to consider is making good, again this can be labour intensive.  Eg PVA/SBR chase, Bond chase, 1 or 2 coats of filler, 2 coats of paint

With the above being said here are the key questions

How many hours a day do you work?

How many days/hours do you think the work will take?

Location in the UK and the travel time to site?

What is your profitable day rate?  Eg some people work for £200 per day or price match however what they need to do is work out there operation cost per year and then divide by 12 and then they can work out how many days a month they want to work and what profit % they want.  This then gives an accurate day rate.

Eg Sole trader could make profit on a day rate of £150 to £500.  However a small company with 10 employee may need a day rate of a minimum of £700 thus paying for admin staff and an office.