A maximum of £35, there may be circumstances when it would be less. But the core point is to book singles if it is cost neutral and the return is in separate jeopardy to the outbound. If it is in the same jeopardy then the risk of separate bookings is 2 sets of amendment fees rather than one. This isn't new logic, it's been like this for decades, but there was a change about 15 years ago which gave greater options to push back the return, so long as it was done more than 24 hours before departure.