An excellent question and thank you to Leakim for helping with the answer. You have to think of it as 2 steps. First you deposit £50 into Ladbrokes and £50 into Betfair. Step 1 - You place a bet on let's say Man U to win their Wednesday match on Ladbrokes and you place the bet on Man U not to win on Betfair. Once the bet has been settled, you will have lost £50 in one bookie but won £50 in the other so you are level overall. Step 2 - You have a free bet and you carry out the same process again but placing the bets of an entirely unrelated match that occurs on Saturday. Does this make a bit more sense?