Show Pairs
They are a company that specialise in the 2-for-1 deals on cheap London theatre tickets. Groups are able to book shows in pairs at a very discounted rate.
All you need do is fill in their information form and if you tick all the right boxes, then you will be put on their mailing list and be alerted to the show pair offers they have each month. Visit www.showpairs.co.uk to find out more.