I think Autumn is the better time to spread compost - I used to wait till Spring, but found that it was difficult to avoid smothering early flowering bulbs. Plus, I have lots of "cooked" compost in the bins in Autumn, last year's leaves have usually rotted down nicely by now to leaf mould and as I only have a small garden, I need to clear space for composting over the winter. As Fidgetbones says, you just need to make sure that the soil is moist - not a problem at the moment after recent downpours! I just tend to chuck it on the soil's surface (ie not dig it in). I find that the worms do most of the work for me over the winter and the plants have plenty of food in the soil when they start growing in Spring.