Need advice! -A dog bit another dog.

[Thiswillpasssoon]

I need your advice please!
A friend of mine owns a dog, American Stafforshire. This 2year old dog was abandoned by previous owner and my friend adopted her a few months ago. She hasn't been fully trained but is really friendly and nice, never had any problem with kids around. One day while she was walking the dog, she found a smaller dog near and suddenly ran and attacked it. When my friend dashed to help and opened the dog's jaw to the little dog suddenly bit my friend.( I know, it's a bit confusing)
Bleeding on her leg, she apologised to the little dog's owner about her dog's attack and gave him her phone number offering payment for its treatment. A few days later, the dog's owner came with vet charge which she was happy to pay. However, she also wanted their apology because that dog bit her too! She had to go to A&E and had a stitch. The owner denied the incident totally and blamed my friend's dog for it too.
So it had to be reported at the police. Although she took some pictures of her wound and left her blooded clother for evidence it didn't prove that the little dog had bitten her. And the dog's owner keeps insisting my friend's dog is so dangerous and she bit her own owner which is not true.
At the first place, I know it was her fault not to keep the dog under control and she has leant a lesson now. She was willing to pay the Vet fee accepting her fault, however, she just wanted an apology nothing else from the dog's owner as well. Is it to much?
In thus case, what's the best thing to do?
Any experience like this? Plz help.

The American Pit bull Terrier and the American Staffordshire Terrier both belong to the molesser breed group, and they both originated in Europe. The Pit bull is taller, heavier, and more muscular than the Amstaff. It also exhibits more aggression and power than its counterpart.
From googling.
Someone local to me has two American Staffies (imported from US breeder) - they are absolutely lovely, friendly dogs - played with mine with no trouble. There is no requirement by UK law for them to be muzzled, etc. They do look a bit like dog in picture (but a bit heftier).

www.preston.gov.uk/GetAsset.aspx?id=fAAzADIAOAAwAHwAfABUAHIAdQBlAHwAfAAwAHwA0

I hope that works. It’s defra guidance which says that AST are of type and shouldn’t be imported. Ones that are already here have to be muzzled etc. Definitely not saying defra are an oracle but if this is their view then I really wouldn’t risk it.

In case my link failed...

Forgive me if I missed this. What injuries did the little dog sustain from the attack?

“There is no requirement by UK law for them to be muzzled, etc.”

The way the breed specific part of the DDA works isn’t actually breed specific at all pit bull type is anything they decide is close enough amstaffs are so close to being pit bulls that there isn’t even an agreement among dog people over whether they’re a separate breed or not... so they definitely would be of interest if the authorities were aware of them.

That’s one of the big issues people have with breed specific legislation, dogs are considered to be dangerous for looking a certain way, even if they’re perfectly lovely well trained dogs, even if it’s actually impossible to have inherited the breed traits because they don’t have any of that breed in their ancestry at all.

Ideally your friend needs to contact Wheldon Law, who are dog specialist lawyers involved in exempting typed dogs (pitbulls etc). That dog could be a pit type, hard to tell the height of the dog from the picture.
To exempt a dog, the owner needs to prove they are competent at a court hearing, have a secure house/garden, keep the dog on a lead and muzzled at all times in public (including the car), neuter/spay and take out third party insurance.

Or she needs to keep her head down, keep the dog on a lead and hope that the police don't visit.

Thanks a lot, all. I myselt learnt quite a lot. Having a dog needs not just sympathy or affection but also knowledge about the dog(someone may think common sense though) and lots of responsibility and decipline. My friend is regretting a lot realizing the situation and will try whatever it takes to save the dog. Thank you for all your advice and even rebuke.