I'm doing an IR/MEP renewal out of Biggin tomorrow. That should be fun
Make sure you plan the drift carefully for the holds. As a guide, around mid-day Heathrow is forecasting 01012KT BECMG 34015G30KT TEMPO 22020G35KT. Gatwick is offering 22020G35KT TEMPO 25025G48KT. Just interpolate...