Essentially, I have a George at Asda mens shirt that is a considerable which my father gave me as it had been far too little (and he's a big) so might be best to go a size up, especially as I am a 10/12 and I'd only wear the L http://messiahspjdq.blogofchange.com/218959/shirtroom-size-things-to-know-before-you-buy