Problem is Jason, there are up to three drop down menu's...Colour (which doesn't affect price), Dimmable (which does) and Sensor (which does).
When the page initially loads I can show the default price, sure, but the customers first choice is colour therefore they'll have, for example...
Colour Drop-Down - Warm White
Dimmable Drop-Down - Please select
Sensor Drop-Down - Please select
This combination isn't available as a product so what's happening is that the price disappears, as does the lookup product code (because there isn't a product with this combination).
That was why I was trying to provide some kind of value for the Dimmable and Sensor drop downs, even though they're sat on "Please select", because the page will assume that those values are the default and, therefore, won't try to change the price or product code?
Does that sound sensible?