@CharlieB93 sounds like you had a stressful day yesterday! Hope you are ok today.
I had my 36 week appointment as planned (at 36w+5) but my 34 week appointment was cancelled. My midwife said that all appointments will now be kept as normal in my trust ( I am in the SW, Hampshire) so I will have one at 38, 40 and 41 weeks. Can you call your midwife/GP surgery to find out what is happening with Antenatal appointments in your area?
About the birth plan, don't panic. The NHS website has a great section on birth preferences, pros and cons of interventions and stuff like that-
www.nhs.uk/conditions/pregnancy-and-baby/how-to-make-birth-plan/
I'm sure if you had specific questions someone on here can signpost you to helpful websites as well!
All health visitor appointments in my area have been cancelled/no face to face contact. If your area is the same, they will send your babies red book in the post (mine arrived last week and I am coming up to 38 weeks soon). When I had my first, the appointment was for them to introduce themselves and explain their role and the red book and also any helpful websites. Nothing particularly ground breaking!
Your hospital trusts website should have the information required about birth partners and changes to provisions/services due to Covid. If you Google "hospital name maternity services" it should come up.
Hope some of the above helps 