I'd like to know what happend to the 'choose semi-flex option' too. Noticed it was gone earlier today when booking my BA2943 EDI > LGW flight home for this coming Thursday.
I'm happy to pay a min of £70 to get 'V' with semi-flex instead of an inflexible one at £55. However, I won't go out of my way to choose 'H' at £105 any more as I no longer need the extra TP (I'm already at 600 for the year and won't make 1500 for Gold by year-end).