UPVC door lock change, bolts

Yes it is there’s a lock called a sash jammer which can be fitted and it locks from the outside

Yes, you can install shoot bolts to the door normally on the existing mechanism

Both are really easy. With the upvc you'd need to call a locksmith to have it Identified and measured up. This will ensure you get the right replacement and dont have to alter the door as much.

Your should not need too. For a visual deterrent buy a pat lock.

You can't put bolts on, but you can put sash jammer on this will do the same job, and yes you can change the locks if you know what you're doing.

Locks can be changed with DIY experience, but a locksmith will have the technical knowledge of correct size of lock & the level of lock security to be fitted. You can fit sash Jammers to UPVC door ( and windows) for extra security - too match the PVC colour ( eg white / brown).