I deeply regret not having stayed in Belgium for a further three months back in the day as that would have given me rights to citizenship and I'd have been a dual national with an EU passport. :o(

Sadly, I can't prove my rights to a Latvian passport, even though I probably have them.

My only possible let in after that is being married to a native Scot if Scotland goes it's own way (and I also have Scottish ancestry myself).