You guess wrong, ‘love flying’. My background is entirely rotary and often involves flying into and out of busy airspace in the SE of the UK.
The current advice from NATS is to definitely notify any planned Class D transits. You won’t necessarily be refused a transit if you haven’t filed a notification but if you have, it increases the likelihood of you being accepted considerably.
Any operators, or flight schools, in the SE of the UK should be briefing their pilots accordingly.