She is a very lucky snake to have found you and it's good you're giving her a permanent caring home. I'm not really experienced with snakes I've only kept them for a short while - my BP is just over a year and the same with my Boa. Maybe she was badly treated by one of her previous owners (I know of someone on another forum who took on a snake whose owner used to beat her - so sad). So maybe once your new girl gets used to you and realizes you aren't going to hurt her and are the provider of food she might come to trust you and calm down - I don't really know but that's the way it works with monitors mostly. Perhaps a snake hook might be helpful?
Best of luck - I'm in the UK too!