I got a quote from Swallowboats to for a replacement boom and sail this morning, sent it to my insurers, Bishop Skinner and they got straight back to me and approved it with immediate effect. So I have given Matt the go ahead and all being well I should have it by the middle of next month. That is what insurers are supposed to do, and it is so nice when they do. I shall now enjoy myself pootling round Poole Harbour at low speed until it is all sorted.
One interesting finding. As the photo shows, it was very sunny. The voltage regulator was showing "High voltage". I unplugged the battery and found that in this sunshine, I could run all the lights and instruments just from the output of the little solar panel on the roof. Not much need for lights in bright sunshine, but it was a practical demonstration that the 10W panels should be able to keep my battery charged all season.
The dyneema forestay seems to be just about the rights length, and the dyneema soft shackle on the jib clew also seems to work, so this winter's modifications all seem to be working so far. The forestay is a bit of a cheat as the jib luff takes most of the tension. I tighten it with a four part handy billy, whilst the forestay is just tightened with the lanyard afterwards. But it is reassuring to have two strings holding the mast up.