Ok, so I am now able to admit it... I am addicted to model of the month.  I like trying just from the pictures and not from the instructions.  

Here is the guitar I made for this morning's charity event.  Think the kids will have fun having their pictures taken with it.

Thanks for this great forum.

It's nice to see you having a go at the models    if anyone else does have a go then please post a picture.
Looking through to see what the model will be for this month now.

I am struggling with this one. I've done everything up to the top of the neck. I used two diamond clear balloons one of the original two popped (there was very little pressure on it, and when I replaced it another one had got a small hole in the top where the pinch twists are. I also didn't leave enough room at the very top of the balloons. This is an aspect I seem to struggle with - gauging how much spare to leave at the tip. Is there any way of improving this?

Are diamond clears prone to popping/springing leaks?

I think it is a case of making it six times one night, hopefully if you lay them on the floor with sixth one will be seeing a lot of improvement from the first one you make.
Measure how much of the balloon is left un-inflated, if the balloon is ready to pop near the end then next time inflate less and if you run out of balloon then next time inflate a little more. As we all twist slightly differently what works for one will not work for the other, try squeezing the balloon a little before you twist to make the balloon a little softer, perhaps that would help. But keep trying, you will get there in the end.

Hope its ok to put my guitar on this thread.  Its not as detailed as yours is graham but its the one I use when I am out working.
Below is another one I did a while ago.