If you have turbo gamble lives and a loss will not take you off of the cash trail, keep gambling until you either run out of lives, then exchange, or you get the top board opened. The turbo gambling often awards a lot of the boxes, and these aren't removed if you lose the gamble (at least they don't appear to be), so, when you get on the board, you often only need 2/3 more to get the DOND feature opened.
Bank it is a handy bonus, as mentioned, and the best thing to bank of course is that DOND game. Watch out when you're in range of that '?' or 'Lose' if you have DOND open, it is often a magnet to one of these squares!
I disagree that the DOND is tight on this one. OK, we've all ended up with a promising board that bombs out to <£3, but taking your £9.79s often yield a repeat.
The best sign on this is if you get the DOND game open, and keep landing on additional boxes that remove low values. I've had it up to just the £15/£20/£35/MS remaining before!
Board costs, however, are an issue on this one, and that is one of the major downsides to it...
