Steve you might want to try a product called tacklewise fishing protection at
Tacklewise Fishing Protection - UK & Worldwide Fishing Cover Insurance. I have just taken out a policy which gives me £10,000 equipment cover, breakage for my poles and rods whilst in use and 5 year new for old cover on replacing equipment. I have also noticed and i will double check with them that as far as i understand if you catch and it is verefied british record fresh water fish the company will pay a one off prize of up to £7,500 depending on what cover you take out. I have just taken the Gold cover for uk coarse fishing for £175.00 for the year and this level of cover gives me the oppotunintiy to claim the £7,500. Worth a look I would say.
Cheers Peter Pike