Please can a parent company guarantee be used if the parent company is not UK?
You can certainly obtain one. The hard part is enforcing it.
Potentially, so long as the parent is established under the law of an EEA member state. Sections 479A and 479B of Companies Act 2006 have everything you need to know.
Eh? What does audit exemption have to do with parent company guarantees?
You don't say for what purpose the PCG is being sought- presumably sought to provide additional security for a debt or as a performance guarantee.
If I were the beneficiary, I would want to ensure that the issuer of the guarantee is themselves credit-worthy. I'd also consider some legal advice as to the validity of such a guarantee and my ability to enforce - and to do so the UK courts.
Be aware, too, if you are seeking the PCG, listed companies are often unwilling to issue them because of fairly onerous reporting requirements for guarantees.
That depends entirely on whether the lender agrees! That should be obvious.