Hello, I am Keith, one of the experts on Just Answer, and happy to help you with your question.
Please can you give be a little more information. Sanzar appears to the a Rugby Football organisation of South Africa, New Zealand and Australia so I suspect that I am not on the right track here. HMRC usually ask for an advance payment of half the possible tax due from self employed traders half way through their accounting period.
Were you trading and in the end the contract value below 60K whilst HMRC are under the impression that this was the correct sum?
Did you have dealings via an EBT through Sanzar Partnership? If you did then you should have a look at the following web site which is quite clear that these activities HMRC consider are pure tax avoidance and covered by existing rules. In that case you have 30 days to lodge an appeal against HMRC's demands. EBTs are effectively dead ducks these days following the Finance Act, 2011 which closed the loophole.
http://www.contractoruk.com/news/0011241hmrc_stalks_sanzar_loan_scheme_contractors.html
Contractor UK offers the following advice:
'EBTs come in many guises and with many different names. If you are potentially affected by the changes and/or HMRC action seek specialist advice. In the first instance this advice should come through the sponsoring company or the trustees.
On a positive note EBTs designed to provide share options are often “approved” and such arrangements are not in the HMRC/Government ‘cross-hairs.’ But again, those potentially affected should consult sponsoring employers.'
I do need a little help before I can assist you properly.