Hmm... Sorry Horace, I'm not sure about that. It looks bigger than it did on google maps!
The discussion at the weekend was productive. There's a planned date for the circumnavigation for the last week in September. I know it seems a long way off but as I can really only practice on weekends it makes it feel a lot closer.
Speaking of wisdom earlier, my friend suggested that a recce trip in the first weekend of May might be wise for me to get a feel for the conditions (the sea is in 'spring' conditions on both dates). Having seen this video made by Sea Kayaking UK of the overfalls at Penrhyn Mawr, I think this is a good idea!
The average speed of a sea kayak in calm wind & sea conditions is about 5.5km/h so to do the 120km or so in a weekend you really need to make use of tidal streams which are strongest with spring tides.
(Un)fortunately the speed of the tidal streams leads to more a more excited sea. Although some planning with the tides can be used to mitigate their strength, at some stage overfalls will be probably be encountered.