Sadly very rare these days - anywhere!
CS TEB the Euro Atlantic is due to/ Or has being retired in Lisbon?
ATA have 1 left, I think on Trooping flights into Hungary?
There are a handful 'floating' around, But the last time I saw an L1011 was in 2005 - CS TEB @ MAN.
Z Air had a nice ex - Caledonian L1011 in the old Cal Colours a few years ago.
I should think you could see an L1011 at Ostend more than likely?
Regards.