I have penlties issued from 2005/2006 for failure to submit…

I have penlties issued from 2005/2006 for failure to submit a P35/CIS36 return in respect of my Ltd Company.
When I received the first penalty back in 2005/2006 I tried to sort this out via my Accountant on numerous occassions. As my previous Accountant would not come back to me and did nothing to sort this problem, I changed Accountants specifically to deal with this issue. My new Accountant said he would sort the problem, although clearly he did nothing. I have now had demands from Debt Management of Revenue saying they will sieze goods to value of £1700 in respect of this failure to submit form P35/CIS36 for year 2005/2006. I have spoken to Debt Management Team and Tax office who say I can appeal, but even though the failure to submit form C135 was caused by previous Accountant, and was not resolved by new Accountant, the responsibility is mine and I must pay this penalty.
My question is this, do I have any grounds for appeal to the Revenue as I did not have any employee during the year in question but it would appear an employee of my Sole Trader business was incorrectly stated as an employee of Ltd Company? I can show employee was paid by and employed by sole trader business since November 2005.
As I can get no help from my Accountant, who promises to phone Revenue and doesn't, who says he will come back to me and doesn't, I am really at a loss as to how to proceed. However, it does seem to me a rather harsh penalty issued by the Revenue for failure to submit a C/135 (all other years apparently are up to date as Nil Returns).
Is it possible I can negotiate with Revenue - what do you suggest I do? many thanks

I have retained copy correspondence from both Accountants.
Many thanks, XXXXX XXXXX (Director) Isherwood Insurance Co Ltd