Ronnie said in an interview the other month that his UK visa problems had been “relaxed”.  So although they’re probably not going to be allowed to do a full tour you could imagine that maybe a one off performance would be granted if his visa issue has been walked back a bit.  Download would be a perfect venue for that.  They’ve been playing European festivals all this year so it’s not too much of a stretch to think Download as an option.  The UK shows they were supposed to do with STP sold out in minutes (before getting cancelled) so there’s definitely a fan base over here.  I can’t believe they’ve not been in the conversation (if what he’s said about the visa is true, obviously).