If it helps, as someone who used to fly a lot when contracting.
RBS, NatWest, Barclays all offer bank accounts that include airport lounge access - the RBS/Natwest one being for unlimited visits
For most of last year I was commuting to London / Bristol on a Monday morning, back to Edinburgh Tuesday evening, down again Thurs morning and back Fri evening - so was in the Lounges up to 4 times a week, all for 'free'.
(the same add on's to my bank account also paid for the replacement of 3 broken cell phones / ipads, a car breakdown recovery service and covered a trip to hospital in Turkey - they must have lost a fortune on the something like £15 quid a month it costs me!)