Hi,
I`ll just add a little to what Standard has already said.
There is still a bias of traffic over the lough but its more like 55% these days. The traffic now is faster and more frequent and that makes departing 04 against landing 22 quite just not worth the extra effort. The 04 dep may thank you for it but the 22 inbound will hold a grudge about it all day if you give him 5 extra miles or god forbid use speed control. If an Atco tells you he`s gonna get you off Rwy 04 when its Rwy 22 in use there is a high probability that he`s just about to stitch up the radar guy!!
The most common reasons why turns over the City are used are for pilot requests or to expedite departures. When there is slow traffic ahead of fast or the clearances we are getting make it the easiest way to provide separation as quickly as possible. Likewise overhead joins for visual circuits over the City its all about expedition whilst ensuring the separation.