Nothing to add really but allow me to welcome you to Flyertalk and the BA Board
Paize. ^
Prior to having status about 5 years ago I would just hang around the terminal (s) when travelling in economy or premium economy. The good news is that should you wish to you do have the option of paying to go into the Aspire Lounge at terminal 5 but I've never been and so unable to comment if it is worth the money.
https://www.executivelounges.com/air...airport-lounge