Have a look at Bradcot website, it gives a list of all sizes.
https://www.bradcot-awnings.co.uk/pop/Awning-pop/
I would check the measurement of your A to B using a ball of string before getting one. There is nothing worse than a too big awning, it will flap about and pool water, too small and there will be gaps at the ends. Bradcot are a good make similar to Isabella and their annexe's zip in either end making for a waterproof fit. You will need storm straps fitted, with an older Bradcot awning these fit on the inside of the awning tensioning on the poles rather than the ones that have straps sewn into the fabric on the outside.
Have you thought about a large porch awning? We have a seasonal pitch and opted for a large porch as it would be easier for us to pitch. Ours is almost 4 meters long by 2.5 meters deep and more than big enough for a table and chairs, storage etc. Most large porches will also take a zip in bedroom annexe as well.