Good result James, nice one.
Its always worth doing those boring Housekeeping jobs on the system I've found, I think of it as "essential maintenance".
From my own experience, I've found a dab of Deoxit Gold on the tip of each pin, then a couple of dips into a pad of "magic eraser" brings valve pins up a treat.
Something like this, not too dear from Amazon.
https://www.amazon.co.uk/Smiths-Magi..._source=1&th=1
Deoxit's under a tenner for a wee tube, well worth it for this kind of thing. :thumbsup: