Cheers!
Also here's an updated build, it'll substitute the < and > symbols with < and &rt; respectively, so you wont need to find-replace next time.
With the other points:
Multiple text boxes: That was me being a little lazy, thought I'd leave the stack-trace visible till all issues were ironed out

.
Input & Output file suggestion:
- I'll play around with drag & drop, something I'd like too, and I certainly agree with the output file idea.
Limiting Output:
Again good idea, particularly for new users.
Thanks for all the ideas

Now I've just got to find the time either side of uni to put them into action and get the code posted up here
