In 1997 the RFU provided their members with a booklet setting
out guidelines on mutual trading as it applied to RFU members. HMRC
was consulted during the production of the booklet and accepted
that it established a consistent and easily applied methodology to
assist clubs in complying with their tax obligations. HMRC reserved
its position as regards the detailed application of legal
principles.
You should refer any case where following the RFU booklet
apparently results in an outcome inconsistent with the legal
principles underlying mutual trading to CT&VAT (Technical).