Hello BJG,
As long as you have the legal right to live and work in the UK then it is more than possible for you to apply for a job with Virgin or indeed any of the airlines based in the UK. My housemate is crew for Virgin and she says there are loads of non-british crew with the airline and I fly longhaul for BA and I am also foreign...(Well Irish is not that foreign but it is a different country), but in recent months I have flown with numourous Spanish, Italians, French, Russion, Isreali, Slovenian, Irish, Canadian, Greek, Scandanavian and Lebanese crew who all have the right to live and work in the uk!!! So dont worry about it, you will still be eligable!!!