Thanks all
Houghy suggested I combine the image into a colour image Id taken previously.
Heres the result of replacing the red channel of a LMC image with Berts lens taken a few months ago (4x6 mins ISO 400 UHCS filter), with the HA image here, after aligning and rotating it. Sure brings out the red nebulae
Thanks Houghy for suggesting it.
The file size of the Ha image turned out to be about 130KB with the level of compression I used to save it at the size I did. Some images seem to compress better then others.
Scott