"From my own circle (industrial R&D, not entertainment or politics), the known, dedicated homosexuals (i.e. those that sleep mostly or exclusively with the same sex, excluding those that might on occasion) are around 1 in 30, so closer to but still rather higher than, 1%."
If your estimating is accurate, it means that your own industry, at 3.3% gay, is gayer than the UK's right-on Channel 4 TV organisation currently is. There was a news story a few weeks ago about Channel 4 announcing new diversity targets for its workforce by the year 2020:
The current LGBT figure for Channel 4 is 2.4%, with a target set for 2020 of 6%. LGBT stands for "Lesbian Gay Bisexual and Transgender". The general public tends to use 'gay' as a non-gender specific word, but in media and government circles they often use the word 'gay' to refer specifically to male homosexuals. The recent Office of National Statistics figure for LGB is a 1.5% average for the UK. (It is 1.1% just for LG, and they don't give a figure for the transgenders, but I would think it is reasonable to assume that the LGBT figure is dominated by LGB) So Channel 4 is already meeting the UK average by some margin as far as I can see. The 6% target Channel 4 is adopting seems to correspond to what the UK Treasury and the gay charity Stonewall think the UK gay (or it might be the LGBT) population is.
Channel 4 also intends to increase the BAME (Black, Asian and Minority Ethnic) percentage in its workforce from the current value of 15% to 20% by 2020. I checked what the current BAME figure is for the UK, and it was 14% in the 2011 Census, so Channel 4 is already meeting the UK average, but they appear to be increasing the figure to 20% to reflect the greater BAME presence in London.