I worked as a locksmith for 10 yrs doing everything locks...lots of lockouts etc.
Probably 90% NDE.
I came across those mechanisms very rarely as they are fitted mainly in continental Europe rather than the UK.
I probably came across 20 out of thousands of locking strips in my time, mostly in good quality flats.
There is a common version in the UK that involves a lever/pad(on the exterior) rather than a handle and by just pulling the door closed you could latch, thus secure, your door.
It's easy to bypass because the doors not locked only latched.... PVC stretches if you get what I mean.
This is in Salisbury?
Looking at that front door if it was a latch only I'd be in there in 5 secs and charge you 60 quid, no questions