That's right, when I joined the RAF I wasn't allowed to wear my Green Beret with an RAF badge in it........no way! They even made me wear RAF wings instead of my RM wings. No 'dagger' was allowed either!
I even LOOKED like an RAF person when they had finished saying NO!
Derek, You were entitled to wear your Dagger on your sleeve.
My local high fashion surplus store has a huge basket with loads and loads of assorted badges in it. Give the woman a ring (she runs it by herself so may have a reasonable idea if she has any in there) on 01234 353136. Its in Bedford but she may well post them out to you as they wont weigh too much....
Try http://www.army-surplus.co.uk you can deffinetly get the dagger badges' in there (both red and black and OD), it's a crackin' site. I've bought quite a bit of kit from them in the past.
Maybe you could try SASS it's mail order kit supplier i'm pretty sure they do dagger patches both Red on black and Black on Green. You can get hold of Catalogue for free just grab a copy of Soldier Magazine they advertise in their