Help, UPVC door lock broken

I have a key stuck in my front door lock, the key is turned by 45 degrees so i cant remove it or the lock barrel (i know how to do this and have removed the screw from the side of the door)

Luckily the key is on the inside (of the house) and i can still shut the door and lift the handle to engage the 'hooks'.

Because of the orientation of the key i cant remove the inside door handle (but I'm not sure doing so would help, guess i could snap the key if this is essential).

How can i get the barrel out when i cant align the locking mechanism to allow me to slide it out? (if i can get the barrel out i can get myself a new one and fix the door myself).

There is a metal strip screwed down the whole length of the side of the door, would removing this allow me to get to it?

Are you saying that the key will not turn at all ?
DC77

Correct, It rotates fractionally but thats only the slack in the mechanism

Sounds fatal. If you really want to try DIY then I would suggest cut off the bow of the key to allow handle to pass, leave exterior handle on and break the cylinder (there are other references on how to do this). Remove cylinder and see if a new cylinder will operate the lock. If not then it is a new multi-point or parts of the mechanism needed.
The multi-point will come out by removing the threaded screws (similar to a wood screw) holding the strip to the door. If you find machine screws, put those back, they are holding the lock and gear boxes to the strip.
DC77
Teamlocksmiths

have you tried using penetrating oil from a spray can? it may help you get the lock open so you can replace it.