It's strange as everything points to it being this very low sight, Chambers diagram shows it as this one, Knibbs shows this one too, I can't actually find one on Protek supplies that's specifically under the Relum Telly/ LP25 but then, They have a Tornado page yet there's parts for the Tornado in the Telly page!!
I think I'll make a rear leafsight to screw down to the block that's already there, This would probably be the easiest!!
John
The protek sights are the correct ones at £6 each, under relum spares number R30 they are on there with a picture of them aswell.