From Bridge Street there is small black gate opposite the Broad Face public house (pictures below), just before the bridge. Go through the gate and into the gardens along the river front. You can also enter the gardens through the iron gates in the Old Gaol courtyard. Please remember to bring your mat.
There is plenty of parking just over the bridge, two hours parking is free.
If the weather does not look suitable, please check my main yoga page for updates and cancellations.