Well, I'm in the UK and I just spent a year looking for a development job, so even some of us locals are clearly finding the market quite challenging. You could look at the main job search sites for the UK to see which skills seem to be in demand e.g. try
Jobserve. There is a lot of noise about "big data", analytics and so on, although I'm not sure how far this is reflected in real job opportunities yet, and I would expect most people recruiting in this market to be looking for people with data-oriented skills, not just mainstream Java EE developers who've done a bit of SQL. Any project doing serious "big data" work will need serious "big data" skills which are quite different from mainstream Java EE.
More generally, the trend in the last 10 years has been for mainstream work to be outsourced to India - so the reason you may be having trouble finding a mainstream Java EE job in the UK is because many of those jobs have already been moved to India instead. There has also been a related trend for importing cheap developers from India, but this is most often on "intra-company transfer" (ICT) permits, which allow companies with Indian offices to bring their own staff from India to the UK for a limited period while paying low wages and avoiding UK taxes. This is mainly done by the big-name consultancies, especially for government projects where large profits can be made by the small number of companies who are able to access these contracts and who increasingly dominate many sectors of the IT market. This has removed many jobs from the open UK labour market, even though they are still UK-based, because these roles are staffed from the consultancy's offshore bases. So you could aim for a job with one of these consultancies and hope to get moved to the UK, but as you've probably seen on this forum, there are a lot of Indian developers who are competing for these "on-site" roles.
Of course, you say you already have a UK work permit, so perhaps there are other routes open to you, but I'm not sure why anybody from the UK would be looking for a mainstream Java EE developer in India unless (a) they need specialist skills that are not available in the UK, or (b) they want to pay you less than a UK-based developer because you're in/from India. You'll need to figure out for yourself which of these categories you want to compete in.