Can you shrink a Harris Tweed new era cap by a few cm 3-5cm Also can you shrink the front panel as well and is there a shop which can do it for you in the UK?

You can shrink or have a Harris Tweed hat hemmed down a few centimeters in order to have a better fit on your head. Your best bet is to try washing and drying it in the dryer first, but be prepared to have the hat come out a little too small.