You do sound like you had a bad experience. To be honest the element of what you bring to light exist in most countries employing overseas workers. I think it is fair to say that if you train as a physio in the UK, then you should hope that you are offered a position as opposed to no job at all and that a foreign candidate should not get a job in the public health systems above the UK candidate. This would seem fair for any country.
There are areas of the UK that have a high proportion of one culture vs. others. This cultural strength in a particular area and often a great opportunity for foreign pt's to get a leg in with an NHS trust. The language and cultural skills are a great asset and the racism component would be much lower as a result.
Working in the NHS in some areas also offers accommodation and even food if living in nursing accommodation. For the working holiday PT this makes a very attractive opportunity. A couple a used to live with who got married worked here for 2 years and saved enought to go home to australia and nearly pay off their entire mortgage. Should they return now and work in private practice then the money is even more although they will have increased costs of living in that area of practise.
Overall the UK, like many well developed countries does offer a great place to learn. You will often earn a lot more than in a poorer country and perhaps the lifestyle might even be an interesting change. I that said there are few jobs on the ground in the UK right now and they will have to go to the graduates that have no jobs at present, as well they should.
Unfortunately the dream is exactly that, a dream. The reality is always far from it but then is that not a problem with the dream?
p.s. I am an Australian Physio working in the UK and have done so for 10 years. It was a great place 10 years ago for a working holiday. It's not so great right now but then it still does have a wealth of opportunities as part of a life long learning experience. :\