The golf wasn't originated in UHD though.
It is a shame that the EPG isn't accurate (it was showing everything as HD on the channel including the football last night). It may be that such information is not made available.
For whatever reason, Sky show everything in UHD on the Main Event Channel, which means that the bulk of the content will be upscaled. It is largely the main live domestic sports, such as football, cricket, plus worldwide F1 that are UHD. The rest will gain from increased bandwidth, but the improvement will be marginal.
Because it is the Main Event Channel often it will not carry all of a programme, e.g. the build up to the first Super Sunday game, as it shows a live Football League / Scottish League match at the same time. That can be found by watching one of the other UHD channels - which will only show UHD content.