Help please - flexible hours - employee rights...?

This is exactly the kind of post where Delboy would have been really useful but seeming he's been cast into the cyber void I'll try and help as best I can, right it's probably best you go and chat to citizens advice to confirm things but I think your works can offer you flexi time as it's seen as helping you, that said you need to agree with what is offered but the bottom line is they can change things without your consent if they want to. That said though flexi might be a good idea if they are really alright with you having time off when you need it, also taking leave is up to you and your line managers if you take it instead of going sick then you could argue you’re trying to help as much as you can.
Now seeming you’re employers are talking flexi they’re probably an OK lot but always be on your guard about what you say and to who you say it, loose lips sink ships and all that, I found it hard not to talk to people when I was employed but you really need to keep mum about a lot of things as words can be used as a weapon and work mates can turn out to be less than helpful and they can leak information back to line managers so watch what you say, oh and take loads of notes and record times and dates and take copies of all sick forms and other paperwork it could be handy later on, it's also a good idea to write everything down so you know what’s been said and to who and when.

Now lthe word you want to watch out for is capability, this law is a catch all, sadly they can use it to dismiss you if they are heartless enough, the crazy thing is the illness you have means you might not be able to do the original job you were employed to do and if that’s the case then you getting ill means in law you’ve broken your contract of employment, crazy I know but that’s how it is I’m afraid, I had it used against me from the first day they knew I wasn’t going to be able to go back to my old post.

Now is there a union at your works?, if there is are you in it?, if not then I'd suggest you join it as soon as you can they can help with legal costs if things get a tad iffy, now if there isn't one there then you could still join a union associated with your type of employment after all it’s your right to do so but if you do I'd keep it under your hat as it could cause you problems if they found out some people have issues with them especially HR bods but then again not all people are as nasty as the one I had to deal with.