Was it too late to plant month-old pumpkin plants?

I dont see why not, they should still flower but later on as other around here are starting to produce fruit from earlier sowings.
They may just produce smaller pumkins... Plenty of water and rich deep fertile soil with plenty of room! and even an occasional dose of beer! Probably not a a good thing encouraging kids to water plants with beer!

Thanks. I have made sure to dig the grounds deep before setting in the young plants. We didnt have money for manure or compost but I did make extra large holes and backfilled with some compost from home. Hope that will do.

Jack be little should be no problem at all as it's such a small squash. I will post a photo of our crop of these back in 2004 on my GOY homepage. After this, I never wanted to eat a Jack be Little again.
(Though this year we are growing the similar Sweet Lightning.)

Bertiefox: are they not nice to eat? We're growing mostly for decoration at @ Halloween time for the kids but I was hoping we could eat some or make a pie.

They are great to eat! I particularly like them when they are immature and more 'waxy' than flowery in taste. My comment was that we had so many we got completely fed up with them! By the way, the ripe ones store until around February, by which time they begin to rot, however we store them. (short of freezing of course)