I think style-wise, a lot of the Q presenters are living in the past. They are sticking to what looked good when they were younger, including (unless it's 100% impossible to get into it) the same dress sizes.
The reality for all of us is that middle age spread is not a myth, but a hard-to-fight inevitability as we get older and hit the menopause. Once you factor in illness or any kind of disability, being able to fight off middle age spread becomes increasingly challenging.
It could be that you always tended towards being an apple shape (and it can be cunningly disguised by a larger bosom) and that tendency has taken hold... Exercise may help, but you also have to think about your diet and physiology... and whether you actually have the time, energy and sheer grit to keep working at keeping the weight off the middle of your body
I think most of the Q women need a makeover. I think the only ones who seem to realise they are not the shape they used to be and adjusted for it are Anne Dawson, Ali Young and Jilly Halliday... with varying degrees of success.
Julia is still a very attractive lady, and mostly makes the best of herself. But she could maybe think about a restyle and accepting that she is no longer "in a size small".