I don't remember the correct length / diameter for that belt but FYI the size you want is 1.5mm wide, not thick. 2mm should work too if installed with care. As for thickness it needs to be 0.5mm at most, better a thinner one if you can find it. Or else the belt will not have enough clearance around the idler and will rub against itself. So don't buy the first 1.5mm belt you see as these are usually square belts (that is, 1.5 by 1.5) instead of a flat, thin belt that you need.

I've 3D printed some in TPU and they work with the EME278 that I was able to get working - one ended up being broken despite the new belt.

The 3d printed belts aren't perfect because the surface of the belt facing the PCB can easily end up rubbing against the PCB because of how the belt routes.

Here's the 3mf/stl for it, needs to be printed in TPU in Vase mode and I can't remember whether the 0.4mm thickness requires the 0.25mm nozzle or not.

I bought this https://www.ebay.co.uk/itm/323856142548 the other day, it arrived and fits well. I cleaned and re-greased parts of the floppy that normally need greasing.

It now starts to read a disk but wants to format every disk i put in it, starts to format then stops. Not sure whats going on with it now.

I was thinking of going down the gotek route. Please could anyone recommend a suitable one with 26 pin connector that will work with a T4700CT.

Thank you everyone for your replies so far as well.