Thanks for the suggestions. The problem I have getting these myself is just like Bigmuz7's which is being able to get to the right place on the right day when the conditions occur. A photo of very obvious swell rather than being mixed in with various waves on the swell seems actually quite rare.
Hi Ian - the RNLI is a great suggestion - sadly this is precisely where the example I posted came from
Cant use that photo as no-one is sure where it came from. Mick - will do re Youtube - thanks.
Trimix - have PM'd you