well the BUPA race was a bit crowded, even with the stagggered start - you should be able to do a bit better in a small race - not so many people to go round, the week before and the week after the london bupa 10k my races were both over 1 minute quicker than london (one was actually 2 mins quicker) and they were of the same type - flat road. Big races arent the best indicators, unless your at the front, which i certainly am not
the RW race predictor is a fine tool but some people are better at endurance (more/better slow twitch muscles) and some better at the faster stuff. It predicts i should do a mara in 3.30 but theres not alot of hope for that.
just get a few more 10k races for a better range of data and youll be fine for knowing what is your preferd pace - im taking it that your using a garmin or similar.
happy to help