What the hell is wrong with these people#pic.twitter.com/0knnzzsJsb
You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more
Prosecco Stormfront does it again. Mumsnet should be burned to the ground or investigated by Prevent or the EHRC or something
you jest, but I'm sure counter terrorism are already on to them. They should be if they aren't.
It's not particularly good advice as something clearly criminal like this could well result in a request from the UK police. Protonmail will release info about the account if it is asked by law enforcement and it is illegal under Swiss law - (IANAL)https://protonmail.com/law-enforcement
They will release IPs (Assuming they've not also used tor/vpn - also recommended on Mumsnet) - given they think it is "safe" they maybe didn't use tor. Worth a go if your local police know how to request!https://twitter.com/ProtonMail/status/1127928367322472448 …
Did you let @MhairiBlack know her name is visible in the screenshot? You should maybe give her a heads up just in case she gets similar random emails from this "woman" 
Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.