how to avoid hitting someone else doing exactly the same?
The sky is big and planes are small
Why wouldn't a 800ft cloud base make an Elstree approach legal? Depending if I'm over built up areas, i could descend to 500ft VFR, no?
800ft would make it a lot safer.
In a
G-reg, it is not illegal to descend below MSA or even below 500ft if you are landing.
so I could take off in the soup from Lydd, no flight plan, drill on in the soup in G airpace on my GPS.
OK.
Fly around London City TMA like you do on any VFR flight
Might be dodgy due to the glide clear rule - various opinions on the LCY area for single engine planes have appeared.
and then pop down to 1000ft when my GPS says I'm near Elstree and have a look if I see the field? This is fully legal, I don't need to speak or file with anyone?
It's totally legal.
Just make sure you are 1000ft above
whatever obstacles are where you are popping down to have a look around