I have a same-day return coach ticket on National Express for Saturday 24 March which I no longer need. The outward journey leaves from Bournemouth Interchange (Service 035) at 09.25 hrs and arrives at Victoria at 11.50 hrs. The return journey leaves London Victoria at 23.30 hrs and arrives back into Bournemouth Interchange at 01.40 hrs so plenty of time to shop, drop or take in a show. I paid £14 for the ticket but if you wanted to buy an additional ticket from National Express now, online,, it would only cost you £13.50 so for £20.50 you can enjoy a great day out in London.
I can forward ticket to purchaser via email.