Is statutory interest valid for self employed teacher?

I am a self employed peripatetic music teacher and am having difficulties with a parent who has an outstanding debt.

Her son received stopped lessons in October last year and until a couple of weeks ago had not made any attempt to pay. In the months of the debt outstanding I sent numerous reminders, emails etc.

Although I specifically asked if they were 'unable to make the payment' to let me know, a while back, only a fortnight ago have they admitted that this is the case.

Because it has taken 6/7 months, and much time/reminders on my part, to chase the debt up I amended the original invoice to include a £40 statutory interest charge (the amount outstanding is only £90). However, she has now said that the statutory interest charge is not valid as it is not of a 'business to business' nature.

The way I see it is that I have provided a service, for which they do not dispute the service was provided or that they owe the debt, so therefore the charge applies.

Where do I stand?

This may seem like a trivial amount but they have been very rude in all correspondence with me despite my initial patience with their lack of payment. Not to mention her attitude of trying to 'call the shots'.

Any advice is much appreciated.

Hi David,

Many thanks for your email, not to worry.

Well done with the great website.

Best,
Mark