Meter readings: multiple meters

I am trying to switch to Bulb. To do that I have to give initial meter readings. But my home has three meters and only one is listed. So how do I give my meter readings?

@Adam_Thomson1 At the moment we only have record of one meter, are you able to send the serial numbers to us via email to help@bulb.co.uk so we can try and get them added to the switch?