@dannytaurus the only thing I'd add is that the 3% conversion fee is carried by the buyer by default, so you don't technically pay that.
This is the alternative to listing in EUR for example, where the buyer would still pay the conversion fee, just through their card provider instead.
The end result should be that you get the same net amount in either case.
If you hard-code a GBP price, you should include the conversion rates in that price to get the same effect.
I totally get this is not great if you expect GBP in your account at the end of the day, so I hope we can add support for more holding currencies by the end of the year.