Am asking on behalf of a friend in Sweden. Does anyone know where you can get (in the UK) red hair clips/bows for Yorkshire Terriers, with a PLASTIC clip on the back as opposed to a metal one?

cant actually see if these are on plastic clips but your friend could email them  http://www.ebay.com/itm/Handmade-Small-Baby-Dog-Hair-Bow-Clips-Clip-Uk-Various-Colours-Free-Shipping-/230878003084?   the also have a face book page.

Ebay seem to have quite a variety I am sure some must be ion plactic clips. I found some on orthodontic bands too

I have no idea about it but i think eBay or Craigslist are best for this purpose to find anything for sale so you can check. I hope you can find easily.

At £2 each they would need to be gold clips

Maybe not suitable but Claires Accessories do little clips and things with the plastic clip instead of metal.  I know this cos my daughter prefers the plastic ones!lol Might work for the dogs hair too(dunno why not)?
But in saying that, me and my dogs share quite a lot of hair accessories!lol I'm forever using their combs and I cut my OH's hair using the dog clippers!!Don't tell him!lol

LOl I use my dog clippers on my OH as well!

I think my friend was thinking that there have to be so many Yorkie/Maletese etc exhibitors in the UK, there must be somewhere these exhibitors buy the clips for the dogs.

You could try, bowsbymarie.com , she makes them, don't know if plastic though.