The problem is here that somewhere along the line they should have advised you that you should have made a payment on account of the duties that were unpaid and in that way the interest is stopped running on whatever amount you pay as a general payment on account. Mind you sometimes depending on how and where you would have to find the money to pay them you could end up cheaper than if you had to take a loan from a third party.
I assume that you are not represented given that you seem to be writing yourself.
There is also another possibility that you were not careless in that you - according to your question - were badly advised. In that event you might not have been careless in that it was the acts of a reasonable man to take the advice of a professional - assuming that it was a professional - and you had no reason to doubt that the person had the requisite knowledge to advise you. In that event you probably submitted your tax return in good faith and was not careless/negligent. The questions are probably their incessant quieries to find a reason for saying that they cannot suspend the penalties.
While you can always hope that they will forget about you I am afraid that enquiry cases are registered on their enquiry database and at some point someone will realise that something has not progressed on your enquiry. However if they did not reply within 6 months I would write and complain about matters and ask for the enquiry to be closed without any more ado and with no penalties.
In truth I think that the investigator may well be referring matters back and forth to their manager given the seeming consideration of penalty suspension.
Always glad to have a chat if it would help on 07751720507
regards and hope this helps
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