I don't know if it differs in Scotland but for my dd's primary school this school year 2006-2007 the inservice days are as follows,
August 14th 2006, day before the school starts back for new school year.
November 16th + 17th, Thursday Friday, making it a long weekend for the children.
Tuesday February 20th, the school had the previous Friday off, the 16th, and Monday the 19th off so made it into a long weekend half term. In Scotland this is the only half term we get we don't get a week like you do in England. The teachers only had to go in on the Tuesday as that was the inservice day, the others were holiday.
And lastly in May the children and teachers are off on May the 7th for the May day holiday and then the Tuesday 8th of May is an inservice day for the teachers, kids go back on the Wednesday.
I don't see a problem with these dates, they are generally attached to half term holidays or the end of the summer holidays. Also on my local council website I can check the suggested dates for the next school year so that gives a rough idea of what to expect.
A friend of mine left our workplace to be a teacher. I enviously said to her how lucky she would be getting all the holidays off and she told me that she wouldn't really get Easter as there are courses to go on then and also in the October holidays there are more courses to do to keep up to date with qualifications, so in reality she said she only really got the summer holidays as the rest of the holidays she'd be working/training.