Hi Wayne,
I have the same bike, and the Haynes manual, and it has similar problems to yours.
Take a look at the front few pages of your manual - it should have a Q & A section which lists common problems. One of them is as you describe and it gives you a rundown on what to do to fix it. Basically, the answer is to start with the spark plugs (check gap, firing etc) then move on electrical bit by electrical bit until you get to the CDI/TCI.
I spoke to a mechanic about mine, he said CDI/TCI is costly to replace but, more importantly, he would go through the same process as described in the manual (i.e. check everything else first) which would be quite costly in terms of time and labour.
I cleaned up the plugs, checked the gap, and now deal with it when it cuts out which isn't as often as before, but I do look a right wally when I've just pushed my way to the front at traffic lights only to have the damn thing cut out at the worst possible moment!
Other than that, I love my little baby.
Good luck,
Angela