Alignment???

[Gar]

Its usually the piston gets stuck and wont go back into the caliper the rubber seal gets damaged and lets debris in or water the piston then corrodes and the rust will stop it moving in and out

If it is the piston stuck id suggest getting another from a breaker or the motor factors and swapping them around its the easiest way to fix it at home

[ChrisJ]

Thanks everyone.
I'll drive it home and see about getting back to that place later this evening and leave it off for the work to be done. Sadly I would have the tools, skill or space to do that work so I guess that'll be another nob for them. Assuming it's safe to drive home and then later on over to them(15mins max each journey)??

[Gar]

Just try slow the car by dropping down gears and using the handbrake

[ChrisJ]

Finally got sorted. 2 new front arms, a calliper and a 4 wheel alignment later with a new track rod end to go in today as well.
It's been a pricey enough weekend but hopefully it won't need much more come NCT.
Thanks to everyone who have me advice on this, it helped a lot.
Chris