IIRC the EU mains voltage limits are 230V RMS +/-10%, i.e. 207V to 253V. (Was harmonized as 230V +10%,-6% from 1995 to circa 2010, which was a lower limit of 216V)
Load it up with a 160W resistive load (or as close as you can to that) and check its output is still within those limits. If so, and if it doesn't overheat in 15 minutes running I'd bet its OK.
If you need to test equipment at a particular voltage, *WITH* *ISOLATION*, put a Variac in front of it.
If you don't have a Variac, use a 20VA 12V-0-12V transformer, or similar, to buck the voltage fed to it in switch selectable 12V steps.