Axminster are sods for that. I have the old 250 tablesaw from the Hobby range from years ago. Very similar to modern versions (apart from ridiculous sized mitre slots).
Anyway, the fence runner looks exactly the same as the current one, so when a very nice chap sent on a longer version for me to use after I built a saw cabinet, I was gutted it didn’t fit the fence.
Turned out, there was a 2mm difference in depth of one low section that screwed up everything.
Seriously not one logical reason for the difference other than they didn’t want people using new stuff on older models.
I ended up customising my fence to make it work, but it’s not the best and a bit annoying.
There are a couple of videos regarding building your own sliding table that look great, this is the most recent I’ve seen