Phil,
I wouldn't worry too much about that. There are thousands of amps on the market in Europe, that were made with 220V in mind. Now we have 230V (which means that allowable voltage is deviation is 207-242V, according to the +5%/-10% rule) and you do not hear about the older stuff suddenly breaking.
Measure the voltage across your AC lines, and if it is less than 240V, I wouldn't worry one bit.