We used to get this type fitted to the doors we had supplied by Sierra Windows in Paignton using the old Profile 22 . I don't know if others used them, I guess they might. If the above don't have them , try Sierra Windows...they may be able to help. Failing that I may have an old one knocking about the workshop
Thanks for replying, I’ve tried every option but no-one seems to have one or even know what I need. Sierra have been as helpful as they can but the companies they are referring me to just don’t have the part. If you have any spare can I buy them off you please?