Thanks a lot for the Info Telandy - especially the bit about Euro tickets.
We managed to get two quite good seats.
I must say though that had I been addicted to the Internet when I started looking, I would now be cured after spending three-quarters of an hour trying to get through the tangle of information to find them!
If anyone wants to go, there is still room if you look under Euro. But I suggest you do your searching on a 'real' pc, not a laptop. The risk that you hurl the laptop out of the window in frustration is very real.
First the site is down. When it functions, you 'book' two quite good seats, only to find that they are nowhere near each other. Try again. Apart from these, except for the very cheapest seats which give a wonderful view of the back of the show, all seats are sold out on the day you wanted. You try all the other performances in turn - there are seats still free, but only single ones.
If you a member of the EF, you then recall reading that bit about Euro tickets still being available. So you look for that bit of the site. You mark two seats, the computer 'refreshes' and forgets where you were. Try again. You find two seats, put all your info and credit card details in, put them into the shopping basket and set off to look for a 'parking card'. When you get back you find that your shopping basket has been turned upside down - your seats have gone. You put the parking card in the shopping basket, cross your fingers sneak back and re-order the seat tickets...
If I had been doing it alone, I would have thought it was my fault, but Mr L was helping and things usually function Ok for him.