I bought a 1.3 engine for my polo after the old one seizing, with the new one being a 4 speed and the old engine a 5 speed, so are the gearbox mounts different ? Just curious as the mount of the old engine doesn't fit onto the new engine and I don't know whether to be looking for a 4 speed mount or I'm just being a tit ? I know a few people put 6n gerbox's on so could that be the case ?

yep, the mounts do differ between the 5 speed and 4 speed gearboxes, you'll need to get a 4 speed mount. Or get a 5 speed box, may be better in the long run if you're changing it all over?

just stick the old 5 speed box and mount back on, the gearbox will go straight on