Hi Tj501,
Three things,
Firstly, if you can fit 420 chain on your current sprockets they aren't just quite worn, they're absolutely cactus. They need replacement.
Secondly, the firm Renolds recommended to get sprockets made was L&M Sprockets in Manton Rd, South Oakleigh. They're right at the very western end of Manton Rd.
Over the years they have made me Villiers engine sprockets, Albion gearbox sprockets and various rear wheel sprockets. I've been happy with them all. It would be two years or so since last I used them. Go and have a talk with them. Show them what you want to replace. Take the sleeve gear out of the gear box and take that so they can ensure the gearbox sprocket is a perfect fit.
Thirdly, if there is room for 420 chain, use it. Don't even think of using any of the old imperial size chain. I only stuck with it because of space issues. It is otherwise a nuisance.
Finally, I always made a point of paying cash on the spot with no receipt. This made sure there was no paper trail to accidentally appear in the domestic accounts. There are some things swmbo doesn't ever need to know. Even if she is happy about it, it will be remembered at an inconvenient time.
Cheers,