Many thanks guys for being there - just looking for someone kept me going. Only saw you at the last minute and managed to scream at someone (sorry, whoever that was).
It all went fantastically well until Mile 25 and then the site of Westminster got me and it went a bit wrong. Lots of strong 'I am a steel rod' power walking later and enormous support from the crowd, I made it over.
OT - I went through at 4.56 so we may have gone through at a similar time (did take me 10 mins across the start though).