The date of Easter is fixed - but according to a lunar calendar, not the Gregorian one.

Perhaps though we could adjust our Bank Holidays to correspond more closely with Wheel of the Year festivals:

Candlemas (Imbolc), or even Chinese New Year as this seems to be getting increasingly popular in some areas, particularly supermarkets - new BH.
Easter (Ostara) - unchanged.
May Day (Beltane) - unchanged.
Midsummer (Litha) - move Late Spring BH to Summer Solstice.
Lammas (Lughnasadh) - move August Bank Holiday back to its old date, first Monday in August.
Autumn Equinox (Mabon) - new BH.
Hallowtide (Samhain) - new BH.
Christmas (Yule) - unchanged.