Hand weeding is about the only way. I know we haver the same problem in our Snowdrop Wood and it takes hours. Not hard as long as the ivy is seedling stuff, but deep rooted is a b...r.

How lovely is that to have your very own bluebell wood!
Tell us how big the wood is. I am sure bluebells bulbs, once established, are very resilient, but like the previous answer I can only think of hand weeding. It all depends whether you have a few square metres or several acres of woodland. I still envy you having a bluebell wood though.
Phil.

the other way is less successful due to the waxy nature of the ivy leaf. in summer when bluebells have died back spray the ivy with a suitable weedkiller. it will work on some sections especially if you damage the stems close to the rooted areas.
personally I'd go for an ivy pulling party. invite friends round with the promise of a barbecue/similar and refreshments and a prize [your decision] for the one who pulls the most ivy. Did this at work once surprisingly successful.

bluebell bulbs are quite deep in the ground so if the area is not too large pulling the ivy away from soil will not be too hard unless it is very well established then it will be difficult if you can do the job before the bluebell starts to emerge otherwise do it when they have died off