I would love £10,000 to spend on my garden!
It might encourage the fencers to hurry up and put mine up. I would like a very... difficult... and partially dead hedge removing and reinstating with another (edible) variety. The lawn area needs some love and attention, so a few tonne bags of topsoil, manure and fresh grass seed wouldn't go amiss. Oh, and some more dwarf fruit trees, so that I could have a little orchard.
I would also buy the big chicken run that I have my eye on, and chickens... who would then trash my garden 😁Bees would be nice, too.