Check the part number for points as I wouldn't be surprised if several models used the same ones. Move the condensor and mount it by the coil (I use vw ones)
A correctly designed expansion chamber, with long front pipe and absorption type silencer can be very effective. Excellent low power and acceptable noise level.
Pull the old one out, it should be marked on it. Or. Measure the stantion diameter, the inner diameter of the leg and go onto bultaco uk site and match the size. The depth isn't to important as you appear to have plenty space.
https://www.inmotiontrials.com/?s=Fork+seals&post_type=product
