Chez Renel is the best price and very good quality.
I did mine, but mine is a French 11B so not sure about the Slough rod config.
It is fiddly but do-able and I have not done one before – results are very satisfying. Just doing my 4CV now with a Renel headliner with a similar type of fitting as the Traction……. but half the size 🙂