Liege [...] as far as I know it has never attracted flights from Britain or other parts of Europe
For those with very long memories, Sabena flew a daily Heathrow - Charleroi - Liège with, I think, a Beechcraft Queen Air.
Liège has had some odd connections in the past, possibly the oddest by a now forgotten regional airline Paris - Liège - Maastricht, the latter sector being less than 40 km.