Back to academia for physics after M. Sc. In mathematics and 4 years working I need your advice. Have a Msc in Math from a decent uni, that I got around 4 years ago. I am working in London at the moment but I really can't stand it any longer. What I want is to go back to uni for a second master in physics and hopefully go on to get a phd. I can go anywhere in europe, but a place that would welcome me even without recommendation letters and being a bit older than the average student would be better. Any good uni to suggest? Alternatives?
Really hope to read some suggestions. You can be specific.
First of all, I would say that you need to be sure on which are your academia aims in the mid-long term. If you really want to aim for a PhD and you already have a Msc, it might not be very useful for you to aim for a second one (unless, of course you really, REALLY want to). Groups nowadays are pretty interdisciplinary and having multiple background in a lab is not only allowed, but welcomed.  

That said, coming back to academia, even after a long period, should not be a problem. Nowadays most grants are milestone-base (that is, x years after finishing the degree, the PhD...) so even as an older PhD student you shouldn't have any problem. At the end, all that matters is that you can convince a PI that you can bring some expertise to the lab, and, if you are eligible for grants the better. The recommendation letter part... that might be complicated. Even if it is not directly from your last employer, you might need something... maybe from your advisor during the master thesis?

If you are looking specifically for suggestions, and you are OK with moving around Europe, at this point I would suggest to search for opportunities in Switzerland. For all intents and purposes it works as a European-associated country, it has pretty high scientific standards and also offers quite good conditions for PhD students. This last part, specially I can tell having done my PhD in Spain where investment in science is not a priority.

This, of course, depends on your fields and topics of interest, but I would give some thought to the EPFL and the ETH, the two federal universities in the country. They are very welcoming to foreign students and offer quite good opportunities. As it is out of my field, I don't know about good groups focusing on the field of physics, but I'm quite sure that with a bit of search you might find some interesting labs.

hope this helps!