[Solved] Contact Order

Hi guys,
Ok so my story..... When I divorced my wife a few years back we didnt' agree a formal access agreement. I was at the time living in the same town, so I'd have them every other weekend Fri-Sun and my ex would drop them round in the week when it suited her as she was off out etc. I then met someone about a year ago and have moved about 45 minutes away , to start off with I still had them every other weekend, then last summer she announced that she'd enroled one of children in a club on Saturday mornings so I couldn't have them until lunchtime - I wasn't particularly happy about this but let it go, obviously when it suited her she'd phone up and get us to pick them up on a Friday night instead. The last 6 months or so she's been particularly awkward, quite often phoning us on a Thursday instructing us we had to have them on the Friday instead of the Saturday, or get them back 4 hours earlier on a sunday, or 4 hours later on a sunday and in particular requesting us to have them Sunday night and she'll come and pick them up Sunday morning before I start work (5.30am) and then take them to school. If we are able to then we obviously take them (apart from the Sunday nights as I don't think its right to wake children up at that time on a school day) but on ocassions when we haven't been able to meet her orders she gets all agressive and sends lots of texts about what a bad father I am and how I don't see them enough. It all came to ahead in May when we had them for the weekend and received a text on the Saturday telling us they had a dance rehersal at 12 on the Sunday so needed to get them back for 11.30 instead of our usual 4.30pm. We were actually away with my girl friends mother and father and had a wedding anniversary lunch on the Sunday planned so refused. She has now decided we can't have any access at all. I am planning to represent myself and apply for a court order to have them every other weekend but am wondering how things work if you're away etc (I'm getting remarried next year so talking about a honeymoon etc). Can you write into the agreement that the order can be amended for holidays etc if enough notice is given? Also I know she's going to want the agreement to include us having them for half of the holidays - can we refuse this (not because I don't want them but because I can't commit to the timings and amount of time, I'm self employed so don't get paid for holidays and if I'm working on a big contract would be unable to take that amount of time off - all my holidays etc have to be planned around my work and can quite often be quite short notice). How does the contact order apply to varied dates - can you draw up a 6 month plan??

Many thanks for any advice