jeez listen to the preachers
none of which have ever done it ( my ass )
people in glass houses etc
Would the Inland Revenue be the reason for your defection to the west, Kev?
I'm a bit baffled as to how he would hope to evade income tax if he intends to register the installation with Gas Safe and the local authority and provide you with the correct documentation. If he can provide you with assurances on that score, I don't see why payment by cash or cheque should be any concern. I'd hang onto a large wedge of the cash until the documents were received.