We went to see it last night, it's fab, recommended by me for children of 7+. You can dress up to get into the spirit of things, you can hear seagulls all around you which adds to the atmosphere, the production is really good, funny, moody - especially the music.
The £7 seats would be Ok if you couldn't afford to see it otherwise but I would say this is worth £22 or £26 especially compared to some other kids things I have seen that cost the same or more. Plenty of swashbuckling for your £££.
GO SEE!