You might take it easy in advance of your flight at one of many lots of lounges at Heathrow Airport. Lounges for example Aspire Lounge provide complimentary food, drink and Wi-Fi, coupled with shower services, from close to £25 per person. BA is currently my most popular solution to vacation. https://www.evernote.com/shard/s629/sh/2baffd87-9e66-b9cc-debc-a4816da9c08e/Kv7Yag83w35ijwcvH76HXOx2h5_w2xbkbdcfEsEQ-D0KAP6D00jYorXwTg