Allotments 4 All

I've got a big clump of alliums (the ones with big heads, not sure of the name). Is it too late to divide them, and if not, what's the best way to do it?

Oh how lovely, I'd say is still a good time as they should roar away in thewarmer weather to come, just keep them watered if we have our usual 8 week drought about this time of year.
The bulbs should be lovely and fat by now and it's a good time to plant summer flowering bulbs!
X s

Thanks- will get out there when it stops raining!