Yeah, we can wear our flags too, you especially see the Union Jack flag embroidered on caps and clothing on sale in London and if the England football or rugby teams are playing in big tournaments. The St George Flag is on Tee shirts, rugby shirts, caps, badges, anything a fan might think to buy to show support.
So no rules on that either
Our Forces tend to have their own regimental emblems / caps etc.. which of course can only be worn by them. Their is no restrictions on our flags -flying them or wearing them