I don't use GWX (at the moment that is) and i'm not sure exactly what tweaks are in it and how powerful them tweaks are,but from various sources I have read,about the conductivity of certain bodies of water in the world,affects how good electrical equipment like ASDIC would work.I may be wrong,but if salt water INCREASES conductivity and the seas around Britain typically the North Sea are high in salt content,this may explain their higher performance when detecting you?
Again,I am not sure if GWX etc implements different types of water,and differing water levels/layers.
And lastly,tactically speaking,you could present the smallest silhouette of your UBoat towards or away from the pursuer,as just when on the surface you are harder to spot face on/away,the same goes for ASDIC,it is harder to detect submerged objects that are face on/away.If your broadside is viewable by his ASDIC that may explain why you are constantly being aqquired.I always try to face him bow first (if he is persistent) and run under him,fooling him hopefully as his DC run will fall away from me as I am going in the opposite direction,then as the DCs detonate you have a few seconds to increase speed as he goes deaf momentarily.If you keep managing to creep away in this way you might get enough distance to increase speed a little,and finally break away.
This is in the stock game mind you,and GWX settings are going to be a lot more stricter
