Mel wrote:

(snip)

I'm wondering if I should bother at all, but
I've been on the waiting list for many years and it could be many more years
before anything else becomes vacant. Decisions, decisions!

All the plots are like that! Unless you are very lucky and move onto
one when the last tenants are moving out quickly. It's unlikely that
someone will leave a good plot behind, even if they move far away from
it. If you choose a 3 or 4 or 5 years crop rotation, that's what you
are looking at for your plot to be good, either 3 years, or 4 or 5. So
start slowly, leave half fallow and green manure it. Don't try to do
everything at once. It might look grim now, and you have a lot of work,
but start with a little shed, somewhere to contemplate from, a kettle
and a good seat. Make some drawings of what you'd like to have and it
will all fall into place ... eventually )