Some good advice on here - another if you don't mind.
I had a patio door set fitted by a friend of a friend about 15 years ago - uPVC - Outward hinged pair.
No complaints - but they do not have hinge security bolts and I would like to fit some.
Any ideas on how to identify what I might need so I can go suitably informed to a workshop nearby that stocks a lot of fittings - and stand a good chance of getting the right items. I guess I need to know that the "profile" is.