I got a reply from Tim; he doesn't have a GPX buy going to try to find the route sheet
Nice one. Please pass on my thanks. I should probably make an effort to get in touch with him myself - will definitely do so if I decided I want to go down the route of making this a perm.
In the meantime, I've cobbled together a close approximation of the route from memory - might be out in one or two small details but I reckon this is near enough:
https://www.komoot.com/tour/270360303?ref=wtdAlso started playing around with variations, partly to avoid bits of road that I'd rather not ride on these days, partly inspired by the coastal route you shared earlier, and came up with this (which eschews Rye for your old favourite - Dungeness):
https://www.komoot.com/tour/274832474?ref=wtd- this uses a lot of cycle paths so probably not suitable for a perm, but could easily be adapted for anyone who prefers to stay on the road. Quite a few of these cycle paths wouldn't have existed the last time the Kent Corners was run.