Stitched up

At the end of last week, I was given the news that I would have to night out on Monday and possibly on Tuesday too. The Monday was unavoidable and I accepted it as a necessary evil but the Tuesday night could have been avoided by getting the material to site 0730 Wednesday rather than 1730 Tuesday, i pointed this out but was told to go anyway. Now when I refer to getting overnighted it involves the following, do as much as you can before you have stop and then try and find some accomodation (Travelodge etc) with a carpark to leave an 8 wheeler in (Only day cab). Once you have found somewhere suitable with a vacancy, pay for your room and meal and claim it back on expenses. Oh and get no extra money for your trouble. I wasn't very happy about the two nights away and said so, but still went and did them anyway. When I applied for the job it was advertised as no nights out. This was discussed at interview and I said I wouldn't mind an occasional one with a bit of notice if it was necessary (ie. delivery to Cornwall) I was told that there had only been 1 night out in 5 years. In August they overnighted my on the Isle of Wight, and expected me to find accomodation on arrival in th elate afternoon during Cowes week. Reluctantly they booked me a room and assured me it was paid, it was booked but not paid so I had to pay and claim it back. There was no reason why I couldn't have gone the next day and been on site at the same time, but it was too important to leave to chance. However it was not so important to them to give me anything for the agro of doing it, I am not bothered by the money only the principle. It caused a bit of a rift and I was told by the HR man that the work load was changing and that this might become a more frequent occurence. This afternoon just as I had finished up for the day, I was told that the HR man was dropping in for a word. They have decided to teminate my employment so that they can get someone else who doesn't mind doing nights out at short notice with no pay. Understandly I am a bit unhappy about this, I have always done what they asked and done it effeciently. If I had refused then it might be justifiable. They have given me a months notice, that they don't want me to work and they also owe me 3 weeks holiday pay, so I won't come off too badly. I have not been sacked nor made redundant, apart they are quite within their right to terminate my employment as I have been employed for under a year. Is this so?