Climate makes all the difference here. It may have passed QC with flying colors at the factory, but once it gets into a shipping container, or transport truck, or sits on a warehouse, then gets to retail and/or your home, the temperature may have swung up and down several times. The woods will expand and contract while the frets don't and since you used the word "quid" it's safe to assume you're in the UK somewhere, which is going to have a different climate than any of the Fender factories, especially if the distributor's warehouse isn't kept at "room temperature". The seasons are now changing and the temperature is cooling, which is why you're noticing it getting worse.
Some woods are more resistant than others, but two necks made from the same tree could probably react differently, due to consistency of the wood being different in terms of density or hardness.
Either buy some fret files and learn how to work on your instruments, or take it to someone who knows what they're doing. The store may offer an exchange or have their tech go at it for a few minutes, but it really wasn't their fault either. It's like buying some clothes that stretch or shrink a little - they may need the attention of a tailor.