Tarik Air 320 from Lagos low approac to LHR?
 

Walking across my yard a few minutes ago I saw an airliner at lower altitude than normal, went in and looked at FR24, just 2,300 ft when most are 4,000 to 5,000ft

You don't say where you are located. If the aircraft was closing the ILS for a 6-8nm final it could well be down at the altitude you mention. However, don't trust everything you see on FR24! By the way, it's Arik Air.

Thanks HD, I am in Southwark. I know what you mean about FR24, but I already knew it was low by eyesight and actually only checked FR24 to see if I was right! Normally at that height and place they loop round under LHR traffic and head to LCY, this one was at similar height to LCY traffic but continued west to LHR. It just struck me as unusual!