Tow Bar & Insurance

So... I have been towing for many years without a problem ,but now seem to be getting concerned that I never informed my insurance that I towed or had the bar fitted. Am I in danger of getting my cover decalared invalid should an "incident" of any nature occur. Advice rquired from the experts please as insurance companies use any contact with them to note your concerns and record them for forward reference.

Barrychas