Hello.
I think the skins are the same, either on the 40th birthday edition or the Galaxy Giovannis : stock LP skins, which many of us (me included) don't like. Lots of people will advise you to change them and buy some new ones.
The problem is that putting a new skin on a drum fitted with a comfort curve rim is said to be rather difficult. I never did it, and plan to change mine once I get the traditional crowns I ordered.
Since you're located in the UK, you'd better find some expert there who could help you mounting them.
If you can spend "a little more" money and can afford shipping costs, Manito Percussion (located in the USA) can provide you premounted conga skins, to the measurements you request :
https://manitopercussion.com/Here's the direct link to the skins page :
https://manitopercussion.com/Their skins' quality is renowned, you can't go wrong with them.