My current one has snapped and is being held together with duct tape, anyone know where I can get one from?

EBay. That's where I got mine.

Do they contain the tension clip or whatever it is that holds the hose onto the engine mount?

That part came off before I realised what had happened, I assume a jubilee clip would do fine too?

Just bought 18-25mm jubilee clip, think it should do the job to keep the breather hose on tight when the replacement one arrives...here's hoping anyways

pipes dont normally come with crimp clips/jubilee clips. even a tie strap will do short term. my pipe didnt come with the plastic joins either. i just reused the old ones tho.