have you tried looking through British search engines? I think I have some bookmarked, I can check later today. I've heard that gypsies moved *a LOT* so it may be one of those difficult lines to trace further. I'd say if you ever get a chance to visit Europe for a month, that'd be the best thing possible
Maybe google terms like "lukas poland" or "lukas romania" or something like that, the last name with the general area where gypsies tended to frequent or live. Maybe "romeny gypsy" too and see where that leads if anywhere. Someone somewhere has to know something, right?
Just throwing those out there, I can' get further back than 1650-ish on either side of my family! You've got a great jump on it already!