anybody from the UK who could help here??

Thanks for the welcomes and for Prism99's reply. I think my wife's been using pure cotton batting so far but was hoping to get Fairfield's 60/40 which she saw recommended by a quilter in the States but I can't find it available over here. Both of those you mention are worth investigating for us. Do they work with machines?

Yesterday my wife that different fabrics require different battings and since she is being suppplied with fabric squares by a friend in the US that complicates matters. Can anyone comment on that. The whole thing is certainly confusing me.

I will say that you must read the batting/wadding packaging to see how far apart the quilting needs to be to keep the batting/wadding from shifting or coming apart. Some say 1 to 2 inches, some up to 10 inches apart.
so the quilting design will also determine what batting/wadding you put in a particular quilt.

Hobbs 80/20 and Quilter's Dream cotton are both excellent for machine quilting as well as hand quilting.

You do not have to match batting to fabric content. Different battings create different effects, so choice depends largely on what you want the end result to look like. You can use wool batting with cotton fabrics, silk batting with cotton fabrics, cotton batting with cotton/polyester/silk/wool fabrics.

As someone mentioned, some battings hold together with quilting lines up to 10 inches apart (these are the battings that are needlepunched through scrim); others need to be quilted 2 inches apart (usually battings that are not needlepunched at all). So, how closely the batting will be quilted can determine which one you buy.

Loft is another consideration. For machine quilting, it is much easier to quilt a low loft batting than a high loft batting. Quilter's Dream cotton is low loft. Hobbs 80/20 is a modest medium loft (between low and medium) and also easy to machine quilt.

Polyester battings are more slippery than cotton and therefore can be more difficult to machine quilt.

Shrinkage is another consideration. Most high-quality brands limit shrinkage to 3% or less. This is true of Hobbs and Quilter's Dream. Someone who does not want any shrinkage at all might go with a polyester batting because polyester doesn't shrink. If used with pre-shrunk fabric, the quilting lines will show very strongly with a modern "harsh" edge. Most of us want at least slight shrinkage in our quilts, as it gives a softer look. Antique quilts, which are thin and soft, typically used 100% cotton batting that shrank at least 3%.

To be honest, I would just get Hobbs 80/20 for your wife and let her use that for the first time. I'd say that this particular batting pleases the widest range of tastes, and it's easy to use. If, after using the Hobbs, your wife decides she wants a flatter batting, try the Quilter's Dream for the next quilt. But I think she'll be happy with the Hobbs 80/20.

Sorry for being so long in responding. This last week's been rather hectic. Thanks for all the input here. It sounds like Hobbs 80/20 would be worth her trying. I know she definitely doesn't want to go 100% polyester.