I'm travelling via Gatwick soon, so I signed up for the gatwick rewards program at gatwickairport.com
I put in my flight number and it tailored vouchers/deals for when I'm flying.
One of the deals is for one hour free lounge access at Regus lounge at Gatwick. Never been myself but usually it's free food + drink and they have free wifi too. Worth it if you have an hour to kill at the airport i'm sure.
Step 1. Go to the deal site or http://www.gatwickairport.com/mygatwick
Step 2. Sign up for an account
Step 3. Verify the email
Step 4. Go back to http://www.gatwickairport.com/mygatwick
and login with your new account
Step 5. At the top of the screen, or if asked upon login, supply a flight in the future. You can just type any airline name if you want to play with it.
Step 6. Scroll the page looking at the deals. Look for the Regus lounge deal.
Step 7. Click the deal / more info bit
Step 8. Click view your offers
Step 9. Scroll to bottom of selected offers page and click the print PDF option
The terms and conditions on the voucher don't seem to suggest anything is restricted (e.g. food/drink) it simply says show voucher on arrival, only valid at south terminal, valid until 31/12/17
lounge is landside & refreshments are tea/ coffee (no food or booze)