A short wall dividing two flat roofs absorbs rainwater, which leaks from
the brickwork into the roofspace below. The top and sides of the wall
were treated with bitumen paint which worked for a few years before water
got in again. This is the wall:

https://i.postimg.cc/sx1Q95B7/roof-wall-20201003-A.jpg

My handyman will paint it again if I buy some sealant. The original paint
was "IKO-pro Flat Roof Renovator" which the tin says is for the flat roof
itself rather than a wall:

https://www.wilko.com/en-uk/ikopro-f...ator/p/0243442

There is also this IKO-pro Bitumen Paint (now discontinued). Is this sort
of thing better for that wall?

https://www.wilko.com/en-uk/ikopro-b...aint/p/0135507

I also saw this Thompsons High Performance Roof Seal:

https://www.screwfix.com/p/thompsons...oof-seal/46708

Igot spoilt for choice when I saw an acrylic sealant Polar Leakseal:

https://polarcoatings.co.uk/product/leakseal-500ml

I'm confused. Which one is best to use?