I don't know what proportion of the population is gay but I would have thought their representation on TV was way over proportion as virtually every programme, ficton or non-fiction, appears to have gay characters in one way or another.Incidentally my Penguin Encyclopaedia puts Chinese below Arabic, Turkish and Greek in terms of ethnic groups.All put together these groups represent less than 2% of the UK population which was put at 60,178,000 in 2002.
In other words, Arabic, Turkish, Greek, Chinese and other minorities only total 600,000 in the UK.