Sliding or Louvre openening Window for my Sliding Door

[THE KESZTHELY KID]

Bezza my 1980 LHD T25 Westie would like an opening window for her sliding door.
Where do I purchase a top quality one from. 
I have seen T25 Middle Sliding Window right LHD with Seal (Sliding door) to 85 OE, 303,30 € which looks a decent job.

FWIW I did purchase one from a certain 'Dyslexic' British supplier and the quality was not great as is it leaked like a sieve when eventually fitted and the window gasket was not too good. My man removed it and it was promptly sent back for a refund.

[R0B]

Let me guess. Was it a company that cant spell campers?

[davidoft1]

The window linked is the same window everyone supplies, no retailer is manufacturing windows