Ah. You’ll find amateurs use WX for weather. In fact, it is used by amateurs who do not speak English and is understood by people who use different alphabets as well.
Anyway, you really do need to read the rules. There is a fair amount to work through unfortunately. But certainly the section on what constitutes a valid activation should be read. You’ll make mistakes at first, everyone does, it’s part of the learning process. I saw some pictures of station setups out in the wilds you posted. It’s always worth practicing the station setup so you can ensure you do not forget anything but it looks like you’ve done that bit already.
If you’re an outdoor type already then you’ll know about how the weather changes quickly in the UK and weather conditions on mountains in Winter etc. So the only thing is to stress you don’t need to take any risks just for a hobby. Don’t be a statistic!
Right, have fun when you get out. Take the walking/hill climbing seriously and the radio will look after itself.