Many thanks to both. I didn't realise it would be possible to repair the spindle wear on the existing carb but it clearly makes sense in avoiding any compatability issues. Grateful for advice on possible specialists to do this. Southern carbs are not taking in new work at the moment - I've seen ads for Gower & Lee and for Coln Engineering - any thoughts welcomed.
Best wishes, Mike
As mentioned elsewhere I used CFS in Bradford for my rebuild. They usually have an ad in Practical Classics but little online presence. A very old school guy in his garage, but he did a good job on mine.