Hi Daniel,
As @theplasterman has kindly pointed out, we can supply it at £75.87 exc VAT, plus £4.95 delivery. You can find it here:
http://www.first4magnets.com/other-c89/thistle-magnetic-plaster-by-british-gypsum-25kg-bag-5sqm-coverage-p8280
And, of course, we are happy to advise on the best...