Austin, im only 15 miles or so from high wycombe, i was born their!!
that aircooled had only 16k miles if i remeber correctly!!! youve done well their austin if it runs well?
your very welcome to drop in for a cuppa if you get time? and tweak the new arrival before you set off, no worries otherwise though.
get a new carb kit, i.e. from ricambio, about £15, has all gaskets u need, + other bits.
i dont know what the others think, but it could be carb flooding? David (126cab) had a problem with his 500 estate, was overfueling and cutting out, and wouldnt start again when hot. turned out to be worn needle i think.
well done m8!!! im pleased it going to a good home!