Hi Andy
The training ride sets off from outside the Art Gallery at 10am (or a few minutes past). The slightly confusing thing is that a couple of other rides also set off at the same time from the same place! Your best bet is to look out for Clifton-jersey-wearers. Kevin and the Clifton social ride (longer but slower than the training ride) gather on the left hand side (if you stand facing the front of the gallery) - if you introduce yourself to someone there and say you're after the training ride, they'll point you at someone who's doing it. There tends to be another training-ish ride led by a local rider who's not a Clifton member, which tends to be longer (sometimes MUCH longer) - so DO ask.
I won't be out today, so enjoy, and hope to see you sometime!