I've not learnt any other languages, just some beginners Java.
I've recently been employed by a large financial institution to do ACA training, which once completed, I hope to use to move into banking. I figured a Java qualification, on top of ACA, would make me look a more attractive hire to a bank.
Ok. There's others on here who can provide better advice on the banking side as that's not a sector I know that well. I'd hazard a guess that it won't hurt, but whether its worthwhile doing the extra work on top of the ACA training is going to be a tough call. Lots of factors involved.
If you were to be going down the pure development route, then I would say definitely go for it, as you likely have nothing else that will get you past the initial screening filters when applying for development jobs. If your CV has no qualifications, no previous development jobs and nothing like participation in open source visible, it will go in the bin. Harsh - but that is how it works - your competition will have some or all of those.
If you're looking at a hybrid role, using both sets of skills, then the qualification would help, however using both skills in a practical application would count for a lot more. If some part of the AQA learning or coursework can lead to an application you can build and demonstrate then you will have a real advantage. It doesn't have to be production quality, just simple enough to show you've thought through what is needed and put the ideas together as a proof of concept.
And finally ... use the big advantage you already have - your employer. There will be people with the kinds of roles you are looking for already there - and the company is investing in your training - so you should be able to approach them and ask what they do, how they got started and so on.