"The Britishicon Sniper, A Century of Evolution" by Steve Houghton on page 76 states:
The delivery of the rifle began with an initial batch of 400 units after which the production of a second batch of 400 rifles commenced, but after just twenty-one rifles were converted the order from the War Department for the 3T (A) was cancelled.

Additionally this book btw mentions that there is one of these rifles at Birmingham Proof House with an Evans scope, also it shows a picture of one with a PPCo scope (the large one, not the 1918 model). And I think the Knowledge Libraryicon also shows one with a Watts scope.


I currently do not have Ian's books at hands but would need to check at home. Due to that I'd not allow myself to make any assumptions as to whether the contract was ended for lack of scopes or replacement of something else. I only might throw in that the non-detachable scope, which sits offset, a clumsy emergency rear sight and the non-uniform scopes used and the heavy modifications to the receiver itself might have assisted with the cancellaction of the contract.