They'll do it a bit later - should be stunning by end of March and throughout April.

If winter Pansies then perhaps slugs/snail have got to the flowers before blooming?

I find that if they are not in flower in the Autumn when you buy plant them that they dont seem to flower until the spring.
So I make a point of buying ones in flower each Autumn and then find they flower till late December, have a rest for 6-8 weeks and reflower in March.

May be the birds take the buds? Mine haven't flowered very well and I've been blaming the pigeons for taking the buds!

Mine have been the same,but are coming into flower again..just lost one or two..so yours will probably be ready again ,anytime now...