28mm Control Mechanism for Roller blind clutch generic flat drive bracket required

Control unit 28mm or roller blind clutch suits generic small tube roller blinds.

Chain is not included    Rare parts for 28mm tube on roller blinds. Black only available

This product is no longer available and I have been advised that the barrel size has been reduced to 20mm.

Alternative is that I reduce the fins on the product listed below to suit the 28mm barrel.