Sunflower,
I did my own brickwork on a large two storey extension - which I was concerned about doing as I had very little experience and needed to lay almost 6000 bricks. My experience was that, assuming you are a reasonable DIYer that can use a spirit level and tape measure, it proved not to be that difficult. I can not over stress how useful 'Builder's Profiles' were and would definitely say they are worth the money. Because I was prepared to take the time to be neat everyone tells me my brickwork is better than any builders have done near by. I also made sure the cavity didn't fill with loose mortar or rain which would later cause bridging. Of course, there are good builders but many don't care about such details.