I don't have problems with any of the pickups on the market but there was a time when some of the new pickups were fitted with poor quality brushes. Unfortunately there are still some of these poor quality pickups being sold as 'old stock' by dealers who should know better! I always use the brushes supplied by Sean Hawker in Bristol; these brushes are absolutely spot-on, correct grade carbon and very light springs - just like original Lucas. If you buy new pattern pickups look carefully inside the part where the brush fits as sometimes the plastic moulding has flowed over the metal conductor and needs scraping out with a small screwdriver; the plastic is quite brittle so it only takes a couple of seconds.
The angled pickups are LU458865/6, the universal pickups are listed by Wassell as replacements for LU458367,458368. You need the universal pickups on magnetos fitted with manual advance and retard as they reach over the adv/ret plunger casting on the cam ring housing.