Focus looks good. You need to tighten up your guiding or maybe you are just tracking at the moment. Once you have that sorted out you can move forward. Keep at it.
Those halos around the stars looks like you may have had dew on the corrector plate. Do you use a dew shield, if not they are easy to make.
Otherwise a great image, M42 is good object to practice on, because you want long exposures for the nebulosity and short exposures for the trapezium and then try and combine the two sets.
Cheers for the comments,
It was actually my first proper attempt at guiding using a guide camera, where my scope is located I get a little bit of wind every now and then which doesn't help.
Normally I do use a dew shield, but for these I didn't as it went missing after a recent move of house.
Longer subs will just bring out some of the fainter stuff.
