Peter - The 'official' Police issued Enforcers were built / assembled by Parker Hale & Enfield. I have a copy of the original sales ledgers showing which serial numbers were assembled / sold by Enfield.
At the end of the contract there were a number of actions, barrels & bits left over that were never assembled. These parts were sold off to the highest bidders.
The two main purchasers of these 'bits' were Charnwood Ordnance and an RFD in the Durham area (cannot remember his name off hand).
Some of these rifles were assembled and sold as 'Enforcers' which they of course are, but they are not 'issued' Enforcers. (A bit like that US company that bought up all the Lithgowbits and pieces, assembled them and sold them as 'new' Lithgows)
I know the RFD who purchased the business of the RFD in Durham, when he opened the store-room he found loads of Enforcer bits and pieces with enough to build at least 12 complete Enforcers. He has now sold much of these but still does have some bits and pieces (the odd action, forends etc)