Hi Seamus,
You mention that the builders cleans that you are hoping to get are "shops".
Normally the retailer will want to be up and running asap, in our experience it is very rare that the builders will "walk out" and leave you to it!
There is normally a load of trades snagging, whilst your trying to clean! Plus the shop staff installing rails, stock etc, ready for opening day!
Powerful vac to remove dust and loose debris from all surfaces horizontal and vertical, clean with the correct chem for surface, followed by shine, removing paint, plaster etc as you go.
Patience, a large dollop of a sense of humour, ability to act as referee between your own staff and trades, as well as a real need to work under pressure are all required.
Ensure as each area is cleaned, the QA is happy with the standard of clean, and get them to sign off on each completed area, this will negate the need to re-clean areas at your own expense. Report any damage, snagging that you come across straight away.
Offer a fair, but profitable price, and you will find that you can gain a lot of work from this sector. Always work to a plan of action, but understand that any plan put in place will change, often quite radically, however deal with any changes or problems in a professional manner, and do whatever it takes in order to get the job done. Dont forget H & S has to be spot on.
Best of british!
Regards,
Rob