Series 3 Roll cage ?

Hello, Just got a rag top S3 109. I would like to fit a roll cage to it for various reasons, a proper one not a cosmetic one. Does anyone know of a supplier for such a thing. I have searched via Google etc but they all seem to be for 110s. I have read on some forums that a 110 cage will fit a 109 but others disagree.

A search of this forum for S3 roll cages only gives threads from 4 + years ago with no actual solution.

Any suggestions ?

Rimmer bros do a couple but I dont know how good they are.