I recently got an Airfix Sunderland off ebay. It is part built (to a very high standard) and part coverted.
But to what? The front and rear turrets are faired over. The portholes are as they were on military Sunderlands. (not like a Hythe with square windows). The top turret is also faired over.
The original modeller has passed away so I feel a compulsion to try to complete their work as they
intended (to the best guess)

The hull is definitely a Mark 3 there has been some conversion done of the floats (adding a step).

There are 3 portholes/skylights in the roof.

My best guess so far is a BOAC sunderland G-AGE*. I've seen some photos of G-AGER in camo, and pictures of wreckage of G-AGES in what appears to be aluminium.

Any further ideas as to what could have been planned?

Many thanks in advance.