You need to change your provider because there are many who don't impose roaming charges. Blame it on Brexit it if you wish, but the simple truth is you are being taken for a ride by your provider.I need to change my provider because a lot of lied-to people voted for something silly. Seems fair...
Still, I suppose it's a small price to pay for all the massive benefits derived from Brexit, such as, errr, bendy bananas.