DI can be defined-scope or full-scope.

a) Full-scope means they can do a rewire - - without notifying BC by
the DIY-route (£200 fee).
b) Defined-scope means they can wire up a boiler etc - without
notifying BC by the DIY-route (£200 fee).

I suspect a typical BG boiler servicing bod is defined scope DI for
example.

Put simply...
- Domestic - you need to be Competent Scheme member OR pay BC fee for
notifiable works.
- Industrial - you need to be Competent with Insurance. Most companies
want to see C&G 2382 (2392) etc and a whole lot more if it is say a
petrol station.

The former was about a paper trail for dead bodies & undeclared
earnings. Sadly domestic cowboys tend to be long gone and a receipt is
as scarce as "cheque will do". (The Cash Economy from this weeks
experience must be freakin huge :-))