Moving bluebells.

The usual gardening answer is months ago or in another few months time.

Google helpfully suggests "If you want to move some spring-blooming bulbs to another spot, wait until the foliage has turned yellow, then carefully dig them up and let them dry in a shady spot for a few days. Store the bulbs in a cool, dry place for the summer until it's time to plant them in fall."

However, in 2014 the Telegraph's gardening calendar said "With the early spring, bluebells are going over, so now's a good time to lift and divide them. Transplanted in the green 'still in active growth' their roots settle in quickly. Dig up a clump with a spade, making sure you dig deep, so you don't slice into the bulb. Divide them into small clumps (with leaves on) and replant at the same depth. Cut off the flowers - you don't want the bulbs putting energy into making seed."

Given that I'd be pushed to describe this as spring, I think it depends on whether your bluebells are still flowering. That or how soon the building works are going to remove choices - may as well shift some and store some & see which work out better?

Best of luck!

As DFV says, the best time is when they're dormant, or after they've flowered and drawn nutrients back down into the bulb. That said a badger had a good go at some of mine recently and I potted them up - they've still flowered and I'll relocate them in a month or so