Note that these letters are just that, merely letters, even though they threaten bankruptcy. They are not court orders or summons. To bankrupt you they have to go to court. If it's the small claims court you will be invited to defend. If they take the riskier option of serving you with a statutory notice then you must respond or they could bankrupt you without further reference.
I say riskier because this is a high court matter. If you challenge them (you will need a solicitor to do this) and they still pursue you, the whole matter will go before a high court judge. This will involve employing a barrister and if you can show that you have a definite dispute it is unlikely that the judge will allow the petition to go forward.
If, on the other hand, they take you to a small claims court and obtain a judgement against you, then bankrupting you would be a matter of form. However, this is usually the last course of action. Before that they would normally brief a bailiff to call and seize goods to the value of the debt.
Kundan Patel, who runs Riks Convenience Store in East London's Leytonstone, has taken the right action. She has written back, recorded delivery, to Lanwall's last known address, to the debt collectors (which will take no notice) and to BoS. This gives her written proof that she is in dispute and claiming breach of contract by her supplier.
For her part she says she was in dispute from day one. "I never buy on finance and the minute I discovered that I was in a lease arrangement I contacted Lanwall but I was told that, as it is a commercial contract, there is no cooling off."
She never reached the required transaction levels of photocopies to make it pay for itself; she never got any of the promised rebates from Lanwall; she eventually got no toner, no paper and BoS wants another £1,603 for the remaining time on the lease for a machine that has already been paid for over and over.
Most recently she has received a third letter telling her a commercial investigator will visit her store "to discuss the pending legal case". Again, this is not official, just further tactics she can tell them to push off.
I have not heard of any of these cases getting as far as court. Kundan says she is prepared to go the distance and I doubt that she would lose in small claims.