How to check if a Power of Attorney will be accepted ?

I need urgent help. 

My purchase appears stuck because the Seller ( a company, which has a POA from the prior owner) is unwilling to register the property in its name before proceeding with the transaction, and wishes to exchange and complete and then utilise the POA to transfer the title/property to me post-completion.   In some way I can understand this as they have bought the property to facilitate  a part-exchange deal, and I assume they now act for the previous owners - that is using the POA its as if I'm buyng from the previous owner and the title will pass from them to me, by-passing the company's involvement. 
My solicitor is unsure whether the POA is acceptable to HM Land Registry because it has 2 donors and 2 attorneys listed in one document, which is apparently non-standard.   Is there any way I can ask HM Land Registry to review the POA (which has two donors each appointing two separate attorneys, all combined into one POA ).  It appears to have been drawn up specifically to relate to a property sale, rather than as any type of general POA.     

The only way to know at present to is complete, but I risk having the TR1 rejected because of a faulty /unacceptable POA, which then exposes me if the seller won't correct this.

HELPPP !!!

Steven - You need to discuss this with your solicitor.  

If they are unsure about something they can contact us through our normal channels, though we normally would not express an opinion without sight of the application which is linked with the POA.  

Thanks Nimish - this is precisely the issue….without submitting there is no way to know, and this is then post-completion.  I have discussed this with my solicitor. The seller’s solicitor is insisting the POA is acceptable but this can’t be verified and is subject to HMLR’s acceptance.  I’m relocating from overseas in 4 weeks after 17 years working abroad and need this purchase securely completed soonest.  You say “ normally wouldn’t express an opinion”, so does this mean in an emergency / expedited situation you could ?

Steven - In some situations we would consider the matter prior to an application being submitted.  I would suggest your solicitor contact us through our normal channels and set out the situation. 

Thank you.