Hi,
Ah, I see it's a "Current Transformer" rated at 1:1 and "2 mA". So it needs a (high valued) series resistor on the primary (mains) side and a (low valued) shunt resistor across the secondary (measurement circuit) side. However, we really need a circuit diagram (and/or data specification) for the complete module.
If one looks carefully at the (ebay) photographs of the complete module, there appears to be a SMD resistor (R13) marked "8M" near to the terminal block. But looking more carefully it may be "824" (i.e. 820k ohms), which seems more likely. That would dissipate about 70 mW at 240 volts, but the average current would be only around 0.3 mA. However, I wouldn't be very "comfortable" applying 240 Vrms (~350 v peak), let alone your 440 Vrms (~650 volts peak) to that little SMD resistor. Therefore, I think you should add a suitably rated external resistor of at least a similar value (820k ?) in series with one of the terminal block connections.
But neither that board, nor a PICaxe is accurately "calibrated", so to set up the mult-turn Pot on the module, you will need an accurate reference meter, of the "True RMS" type if you really need an accurate RMS measurement. However, if the signal to be measured is basically just a Sine Wave, then a simple Peak to Peak measurement, using the standard scaling factor, should be sufficient.
The PICaxe ADC (and virtually all micro-based devices) measures an "instantaneous" value which in your case might represent any value between +650 and minus 650 volts. Thus you need to make multiple READADC10 measurements (maybe hundreds) and then filter and average the values. The "filter" is needed to eliminate spikes and you can't use a simple "average" because the average of a symmetrical +/- waveform should be zero ! But a PICaxe program should be quite capable of making the desired measurements, probably with a simple Max - Min (i.e. peak to peak) detection algorithm, or a True RMS algorithm if really necessary.
Cheers, Alan.