Set up two separate company's , one industrial work vat reg, one domestic non vat . Simple!
Very grey area!! Even the VAT people give different opinions as to whether this is allowable.
The companies would have to be completely different, i.e, different address, directors, phone numbers, vans, employees, bank accounts etc etc.
If you owned both companies HMRC might decide it's just a ploy to avoid VAT and then you're in the poop!!