So Bianca went off to Milton Keynes, which is not far from London... So Kat is hurt in the fire but as we know I guess she will not come back and visit her in hospital .

I was thinking this in her exit episode, next week her best friend nearly dies and she'll be nowhere to be seen!

Maybe she'll visit offscreen?

I have no idea why they don't reference more offscreen visits for the sake of believability. It would have saved Michelle Fowler an awful lot of broken bones and illness over the years.