Fancy Navigator
I am not sure why descending in the face of heavy rain would help, because rain tends to fall downwards also. You would have to descend below ground level to avoid it. I know there is some rain which exists only at altitude (the name for it is something similar to Viagra
) but that is rarely true for heavy rain.
The best thing, if you really MUST fly around in UK weather, is to get the IMC Rating and get your hands on a suitable plane. Provided you are able to put in the hours to maintain a reasonable currency afterwards, it isn't a bug deal and will hugely improve your confidence and your ability to actually complete a trip and get back.