Lower Washer Fluid Warning / Checking ECU

I had my 2015 X250 3.0D S serviced this week. When I got in the car today, the "Low Washer Fluid" warning came on and I immediately thought of the well known fault where a leaking washer pump can ruin the car's electrics by leaking water onto the ECU. I tried to check the actual level of the water but despite my best efforts couldn't see the level - is there any way of checking the actual washer water level, just in case it is the sensor that has failed rather than the water level actually being low?

Also, am I right in saying that the ECU that can become corroded by the water leaking, is the one behind the removable door to the right of the accelerator pedal? I checked this and as far as I can tell it's all bone dry.

Mine is one of the very last X250s, produced in mid April 2015 and the VIN is later than the one mentioned in the Jaguar America bulletin on this issue so in the past I've assumed won't suffer this well known fault but on reflection, I think it's worth me booking the car into a specialist that knows of this problem to get it checked and to go for the spliced wire modification - even if my car is a later one which wasn't affected, I think the mod is worth doing for piece of mind. I'll also ask if they can check if the washer pump is leaking and whether any water has got into the ECU area so they can dry it out.

Am I right in thinking that the battery doesn't need to be disconnected to do the wire mod?

Many thanks in advance.