I'd go direct from Earls Colne to Cambridge at 2-3k and call Stansted and ask for "transit the NE section of your controlled airspace at 2k from Earls Colne direct to Cambridge".
Keeps you out of the way of too many gliding sites. They might say "not above 2000" or something and IF you don't get a transit you can drop down to 1400' (bit low for my liking though) or scoot further east.
by talking to them you are unlikely to infringe them, and if you get lost then they can help before it becomes a crisis.
just my view...
PS I also wouldn't avoid the 2500 bit of Class A to the SE of STN but go below sub 2500 DCT EC. You will be down there anyway as the TMA is at 3500' and you'll be landing Earls C. Much easier than jiggling about all over the place.