Our solicitor looked over ours straight away and said it was Polaris's typical contract and nothing really to worry about unless you strongly oppose to any conditions, I'm sure there has been many thousands of contracts signed already.
We sent ours back before the 1st payment was due.
You have to make sure your solicitor pushes for the bank guarantee after your 1st payment but before your 2nd payment is due. Polaris are reluctant to give this as they have to pay for it. Our solicitor said we shouldn't make the 2nd payment unless you have it.
We have received our 1st guarantee and since made our 2nd payment, we await the guarantee for our 2nd payment.
Mike