Hi,
OPT in the states have a series .965 eyepieces. They're standard Possels with stepped down barrels and they're not that expensive. I bought a 25mm one for my old 114mm reflector and it works quite well.
Website is
https://optcorp.com/collections/0-965-eyepieces
I believe that .965 diagonals (along with those truly awful .965 Huygens) can be picked up on ebay or Amazon.
Cheers,