I am in a similar position
The saddle that came with my ebike is starting to get worn out - the surface coating is cracked and falling apart so it needs replacing
The saddle has always been just right for me, in spite of it just being the one that came with the bike
Selle Royal so a well know brand
BUT
apparently this particular model is only sold with pre-made bikes - you can;t buy one on its own
only the Gods know why this makes sense - but.....
anyway - the LBS is very helpful - but for saddles he just points to 3 on th ewall - in different styles - and says those are what he sells
and none look quite the same as mine
only other bike shops nearby are the big brands -
Halfords and the like
I do have 2 other saddles - one came with my wife's folder but it is too narrow for me on long (for me) rides - OK but not ideal
I got her another one but that is too wide for me
which is a pain