import nhs calendar

I would like to sync and combine my NHS mail calendar with personal and family calendars on ical on my Macbook Air. I can do this by adding an Exchange account and selecting the calendar tab. The drawback with this is that my NHS mail password changes every 2 months & I need to remember to change in on all devices or else I get locked out of NHS mail. I guess this is a security issue? NHS mail won't allow sharing of calendars by using urls? Many thanks