They can’t send letters pressuring you to go back, you could get your union involved if you’re Off sick your off sick they shouldn’t be contacting you. You can speak to your gp to extend sick leave as well if you feel you need to x
Are you in a union? Definitely speak to them for advice. There should be absolutely no pressure to go back. You may well want to notify them of your pregnancy- for extra protection.. they'd be beyond silly to be pressuring somebody pregnant to come to work when they aren't fit to.
Hi, are you able to send me a message? Not sure how it works on here x
I would tell them when you found out, they can't then force anything on you. Make sure you have correspondence through email just incase you need it in the future. X