many of the parts can be easily made eg the nut bridges under the capping are just bent flat bar with a nut welded in the middle
there is this site that you can see all the parts
Buy spare parts for "Hard top - TR2, TR3, TR3A and TR3B" of Triumph TR2 to TR4A (1953-1967). ✓ large selection ✓ professional support ✓ fast delivery
www.scparts.co.uk
i and sure dimmers and moss do the after market parts as well.
the real specialist parts are the 3 brackets at the top the screen
and the chrome cap covers 5 of 2 sizes around the back.
this was mine ( non standard finish)
www.tr-register.co.uk
i had to move my racing roll bar but after that it wasn't toooooooo difficult
as usual lots of measuring and offering up the top for location, slacken off the front screen mountings to help AND fit your side screens as they all come into play at the same time.
rubber parts ( non specific ie don't look for tr2/3 hardtop rubbers ) are available here if you get stuck
Phoenix Trim supplies Trim Seals & Rubber Extrusions for every purpose and specialize in selling off the roll. Check out our online 'Classic Mini Shop' and our 'Main Catalogue' of over 1'000 profiles.
phoenixtrim.co.uk