can she do this?

I'm after a bit of advice about work (again!)

my assistant manager has called a meeting next wednesday morning, and told us all that we have to attend, but I had arranged a month ago for Sky to come and fix our system (before we go away so hubby can record his programs)
I rang her to tell her this and she told me she didnt care and that I'd have to rearrange it because everyone had to be there.
Now I'm just womdering (because in having to rearrange Sky she has pissed off my hubby and meant it will be another month before they can come out and fix things) if she is allowed to do this?
I know she cn call a meeting, but I thought she needed to consult staff on the best time/day for all of us, and at least give 7 days notice....?????

Now I'm only biding my time until i can qualify for MA (naughty I know but I am really begining to hate the place and that isnt good for me, or my family) - which is the 20th of Oct....
I've already been told about a job closer to my house, same pay similar sort of hours...... so I am thinking of going for that as well because even though I would qualify for MA it wouldnt be until next year, and with Xmas coming up things might be difficult... (plus it would mean hubby didnt have to go back to working 70 hour weeks)

I was wondering if anyone knew about this (I know it sounds petty) or if they could point me towards the right part of employment law as the only ones that come up on google are for disciplinary and its not that...
I've checked my contract and it says nothing about meetings at all.

Thaks for any help or advice.

xxxx