I am based out of India. Irrespective of the location, being in this domain for 2+ years now, I can tell you that while there may be comparatively few open positions, the pay (irrespective of location again) is above par if compared to enterprise but on par otherwise, for experienced programmer!
If you are at entry level, I can think of having a related self project or contributing to any of the numerous open source projects in the scientific stack will do the trick. Hope this helps.
Regarding the pay, I'm a bit worried that it might not be the case in UK. For example, when working in Big Data positions (my current area), it's not hard to get 100k pounds per year or more, while I ads for scientific or graphic programmer (or anything non-enterprise for that matter) rarely exceed even 50k. The difference is that on 100k I can retire before 40 and on 50k I'll probably work forever... If that's indeed the situation I'll probably try getting into the US as H1-B as I hope the situation should be better there.
As for getting a self project - I'm thinking of doing a physics engine focused on static forces - something inspired by structure engineering methods (solving with finite element analysis for example). I have no idea if I can make things bend or break believably in real time but it seems like a cool idea to pursue.
If you are at entry level, I can think of having a related self project or contributing to any of the numerous open source projects in the scientific stack will do the trick. Hope this helps.