my dream has always been to purchase a Hurricane MK1 and present her to BBMF to ensure she stays here.

I think you would have to tie that up in a contract in blood saying if it was ever intended for it to be sold it would instead be returned to your estate, yourself, or the full proceeds of the sale would be, thus preventing it happening… That way there would be no benefit to them selling it on….. I am sure the likes of Portugal donating the JU52 from Duxford they would never have envisaged it being sold on, but who knows there may have been a clause to allow it..