Remember my avocado plant? It's now 8ft tall and rather unmanageable for my small flat. I thought I'd try and palm it off on Kew Gardens or somewhere... but here is my very informative email response. Top marks for Kew though in terms of "visitor satisfaction".

"I'm afraid that for plant health reasons Kew cannot accept
donations from the public, so we couldn't take your avocado. Most
other botanic gardens operate a similar policy, so I can't think of
anywhere else that may be able to help you. However, if you live in
a sheltered area of the country like London you could try putting it
outside - although the books recommend a minimum temperature
of 13 degrees for avocados, as temperatures rise there are an
increasing number of reports of avocados surviving and even fruiting
outdoors, for example here.
This is quite a risky strategy as, of course, many that don't make it aren't
reported, but it may be worth it as a last resort.

If you try growing an avocado again, you can avoid this problem by
stopping the first shoot to emerge from the avocado stone once it
gets to about 15cm. Chop the top off, which will mean losing all
the leaves. Nothing will happen for a couple of weeks and you'll
start to worry that you've killed it, but then shoots will start to
emerge from the side of the main stem. these will be slower
growing and go sideways rather than upwards, and if you keep
pruning them when they reach the desired length you'll end up with
an avocado bush rather than a tree trying to escape through the
ceiling. If unchecked, under favourable conditions avocado trees
can reach a height of 20 metres!

I'm sorry that we couldn't be more helpful."

So there we are. Perhaps I'll persaude my parents to keep it.