Agree. Whereas a non-VAT installer would be lumbered with paying 20% VAT on materials which would put them at a disadvantage against an installer that pays no VAT on materials and only has to charge the customer 5% in this case.
Unless the job price is 4 x the cost of materials, then the VAT reg'd business has the edge.
Unless the job price is 4 x the cost of materials, then the VAT reg'd business has the edge.