I spoke to 2 Revenue people this morning at Basingstoke, No problem with buying the 2 tickets as stated earlier, first thing she said was, no BOJ as not leaving the station.
They both didnt think Clapham counted as London though. However Im not doing that. No need to double back either they both said
So those two Revenue staff have given you permission to break Megatrain's terms and conditions have they? I hope you got that in writing. Could be an expensive mistake if there is a rail-side revenue block at Clapham Junction.