I wonder why she does this?

And, I agree with the long line AND with Callie that this could be a UTI

I think so, too. And I stupidly put a reply for this thread in another thread. I was going to say she might want to consult a professional. That could be a vet, trainer, behaviorist, or all three.

Another thing to think of - sometimes "praise" can actually be aversive to some dogs. We think we're being really nice and friendly by talking loudly and petting them, but the dog sees "This human's gone off her rocker, is making loud and scary and weird noises, and manhandling me! This SUCKS!" If your dog is already nervous to pee, doesn't have a UTI, and you want to try praising her for going outside, try doing it very gently and calmly. Just a few soft words in a happy (not high-pitched) tone might better convey your emotions without frightening her. 

First thing I thought of was a UTI since the OP says the dog is constantly squatting and moving around.

I agree with the suggestion of using a longer leash.  I had Kenya at a show yesterday and it took several tries to get her to 1 and 2 even though I could tell she had to go.  I only had a 4 ft. leash and ended up having to just drop the leash let her go.  Our potty routine is I stand by the door, say "go potty" and wave her over to the potty spot.  She won't potty unless we do the same routine and I wave her over to the right spot, far enough away that I'm not hovering over her.  If I don't direct her, she just keeps circling back to me or stands there staring at me.  Phil does the same thing, just uses a 20 ft. line. 

Luckily, my dog has the opposite problem of other dogs, she wants to come back inside after potty.  Instead of letting her play outside after potty, I stand by the back door so she knows if she goes quick, she can come right back in with me.  For Coke, we try to give him some extra time outdoors during his potty break b/c he likes to be out there and doesn't really care to be with me indoors. 

Oh so sorry just saw your replies, Margaret is still the same, I was thinking about what you said, it it possible though she could have a UTI After we have had her over a year? Wouldn't we have seen other signs?

My fiance on the other hand says she has been worse since I went to stay at my mums, you see we don't have a garden so we have to take the dogs down on a lead and we wonder if she is more picky now as she could take as long as she liked in my mums garden when she stayed there for a few weeks?

She used to wee a lot when you called her when we first got her, dribbles of pee on the floor, she isn't half as bad now.

THANK you for all your advise, How would my vet test for uti? sorry be daft, and sorry for any disagreements my post may have caused :( xxx

Sometimes they can have a low grade UTI that hangs on forever and it isn't BAD enough to really notice.  The peeing a lot when called is submissive urination....glad that's passed now.  But, yeah, she could have come to you with a UTI so you don't SEE a difference because there isn't one.

Don't worry about the fussing....that happens all the time around here!