Tide times
The link below is for the BBC tide forecast, however to make it easier monthly times are below. If I forget to update this, please let me know! Take note of the expected tide height. This generally ranges between 6.1 and 4.3. On the lowest tides you will have a much reduced time on the water.
If you need to use the lock - locking times are daylight hours an hour before high water to half an hour after. Night time lockings are possible with 24 hours notice (and a bottle of wine).