You've done a neat restoration. If you decide to straighten the barrel keep us posted.
Chambers in Scotland will sell you the missing bits needed (Chambers Gunmakers - Airgun, Shotgun Rifle spares. Parts for Air Arms, BSA, Crosman, Diana, Gamo, Relum, Webley, Weihrauch and many, many more).
Look under Diana/Original, model 22.
There are at least two members on this forum who stock old airgun bits, I can't remember their names but one is in Bloem and I think the other is in Pretoria.