I cannot comment on the meaning of "lash-up" - as it sounds somewhat of a "colloquial chav" term to me... Doesn't really sound like a good experience!
despite having paid for a years membership.
Why did he pay a year's membership prior to taking a "trial" lesson? Don't you want to feel comfortable where you're learning? Make sure the instructors are nice / compatible? Ensure the structure suits your needs?
There are quite a few clubs in west of London, so at least you know there are a few options! I personally would have asked for my membership back - stating that clearly, the unprofessional attitude displayed isn't compatible with me and that you made a mistake coming in.