PVC window with odd leg unit?

Morning guys

I need to change some DGU's in some very strange PVC windows, Just wondering if anyone has come across these before and know a trick for getting the glass out.

The units are stepped (external pane is 10mm bigger all around than the internal) Then a 10mm security tape is all around that extra 10mm and the units have then been stuck into an odd leg PVC frame with external beads.

I tried everything I could think of to get them out short of smashing the glass. I cant get a knife to the security tape due to the odd leg frame and a non removable internal white rubber gasket.

Has anyone come across these before? Ive never seen anything quite like it.
I would rather not smash them out as the customers have a brand new kitchen.

Squirt PVC solvent cleaner straight from the bottle all the way round, wait half hour and then gently pull the unit out with a sucker, worked for me years ago when I changed a unit for a customer when they weren't in, don't worry the site manager stood next to me throughout to assure the customer I didn't enter the property.

Did you know this was how it was glazed Gaz, will your new unit fit? I'd check before going to the trouble of taking the old one out

No I ordered a normal unit and only realized when I tried to take them out to fit.
I have got the remade stepped units in now though and will try a good blast of solvent all round.
Quite possibly the strangest PVC windows I have ever come across

Is it ex council house, they normally have some weird and wonderful systems all done to a price, cheaper the better, like single glazed PVC windows with an inch thick wedge gasket each side

It is an ex council house but these windows were different to the rest as it was some kind of prefab kitchen extension.
Yes they have huge external wedge gaskets too.
Strangest PVC windows I have seen in 20 years!