[Evolution] Subscribing to shared EWS non-GAL calendar

[Pete Biggs <pete biggs org uk>]

Evolution 3.36.2 - EWS/Office365 account

I've recently had to configure my home copy of Evolution to talk to our
Office365 tenancy (for obvious reasons!). It was not pain free, but I
don't think it was totally an issue with Evolution.  The only thing
left is to connect to a shared calendar, but the account with the
shared calendar is not in the GAL, so it appears that Evolution won't
subscribe to it.  My personal calendars on my account show up no
problem.

Is there a trick to subscribing to such calendars?  I currently right 
click on the *mail* account in the left bar and select "Subscribe to
folder of another EWS user...", enter the username in the box and
select a folder name of "Calendar" and it just comes up with "User was
not found on the server" - I've tried all forms of the username (i.e.
name, name@address, name@emailaddress and so on).  Clicking on the
'Choose...' button doesn't show the user, but it does show lots of
similar ones, but that's not surprising as it isn't in the GAL.

Does the subscription process check for the user in the GAL before
subscribing?  Can I tell it not to?

Any pointers would be gratefully received so I don't have to use
Office365 on the web.

P.