Are you aware that the new UPVC doors have locks fitted that are not of the highest standard (what a surprise!) I recommend that anyone with these types of locks, new or old, have a free no obligation assessment from Absolute Locks.
Pictured below is the after effects of a burglar snapping a lock, believe it or not the tool they use is cheap and readily available, you can even find websites that show you how to do it.
And if you can, you can guarantee that a burglar can.
After many years experience I recommend ABS cylinder locks, not only do they look different (see below) which in itself can detract a burglar but they also have a unique design feature that gives secondary security if they attacked.
These locks are recommended by West Yorkshire Police in the fight against crime.