You could see the positives in being given an extra 2 weeks physical training whilst being paid for it, or you could start of your RAF career with a ET, your choice.
To think that the RAF would pay for someone to do PT for no sound reason is a bit off if you ask me. According to the Mirror Techs ladies, yes ladies have a different body to men, yes men, you have a different pelvis, apprently you are shaped to give birth and men are not, men are shaped for other things, drinking football and all that.
Anyway mindful that this is a recruitment forum and I am a Moderator too many females were getting broken, not through lack of fitness but through lack of the right kind of activity, so the RAF now pay you to do the right kind of activity for two weeks to build you up and stop you spending your time on holding flight while you get better. You would not like holding flight and you might have missed your trade training slot and therefore kicked back out to get fit and come back at a later date.
To be honest it is a postive measure to help you get through basic and you should see it as such.
Good Luck
This is not remedial you will not get in the RAF if you need remedial as you must meet the RAF standard now as a part of the recruitment process.