A reasonable image Trevor. Sort out the bright blue but don't expect the red colours you will see in my images or those of others using a CCD or modded camera as the filter in front of your CCD is blocking the Ha and is quite sensitive to OIII hence the blueish tones around the nebula.
Tone the blue back and it will be quite a nice image.
If you have Photoshop have a look at this website. It is full of useful info including masking the cores of items such as Tarantula and Orion.
http://www.astropix.com/HTML/J_DIGIT/TOC_DIG.HTM
Keep at it.