Many horserace meetings especially National Hunt [over the jumps] change their start times accordingly when the clocks go back an hour in October. So instead of starting at 2pm and finishing at 4.30pm they start at 1pm and finish at 3.30pm, for example.
I reckon the proposed changes will have serious detrimental financial consequences and may even put many bookmaking firms out of business ;o)
A day is 24 hours long and whatever you do cannot affect that. All you can do is decide how you want to utilise them. To me I would rather have the longer useful time of an evening and so would prefer Summer Time all year round. I do accept that others have different ideas about it, but we would probably need another referendum to decide what we would end up with. Cloxit maybe?