One nice easy way to avoid Stansted is to set 310 on CLN as you hand off from Cottesmore; come onto 130 to, and that'll track you down past Lakenheath CMATZ (friendly and helpful, but sometimes the accents are tricky), past Cambridge (usually good for a FIS), and then when you see the Sudbury masts go straight south.
Southend? Great big huge runway, nice folks, but if you're going to the seaside be prepared to laugh at all the Chav's on the prom in their tarted up H reg Clios.
