Originally Posted by rwoman

As the SLC LHR flight lands around 130pm and the lounge closes 2-230pm, it's not really practical.

Given J2 departs from T4, the Tube will be easier for the return than the HEX (requires a connection at T1/2/3), as well as cheaper. Piccadilly T4/123 train on the return from central London is easy. The Tube to/from central London is the cheapest and better access to central areas than Paddington (get an Oyster card). As stated above, see the UK forum...lots of advice there.