Heathrow Rewards, the shopping loyalty scheme for the airport, is offering a 100% transfer bonus for converting your points to airline miles.
This does NOT include Avios or British Airways Executive Club, unfortunately.
It does include the other three airline partners:
Miles & More (Lufthansa / Swiss / Austrian etc)
The minimum transfer to airline miles is 250 Heathrow Rewards points. With the 100% bonus, you will receive 500 airline miles per 250 points.
Without a transfer bonus I am not a fan of transferring Heathrow Rewards points to miles. Since 500 points usually gets you 500 miles or a £5 shopping voucher, you are effectively ‘paying’ 1p per mile. That is rarely a great deal. I am a lot happier with 0.5p per mile.
The transfer bonuses run until 31st December (30th November for Virgin) so you have plenty of time to nudge up your balance to a multiple of 250 points!
Full details can be found on the relevant airline pages of the Heathrow Rewards site when you are logged in.