On your iPhone/iPad, LOG IN to Caltrics (https://caltrics.com)
Once logged in, tap your email address/account name and tap ‘MY ACCOUNT‘
Tap the first webcal ICS URL link, immediately after ‘Your calendar connection link is:‘ (NOT the 2nd one which contains your email address)
Tap ‘Subscribe’.
Events should appear in your iPhone calendar within approx. 15 mins.