Obviously the next time WC needs updating I will have to reimplement this change, unless anyone can give me pointers to a more permanent solution?
I recommend brining this up to WooCommerce. They shouldn't be interfering with existing caches like this, and I imagine many of their users also have their own caches and are simply unaware of this.
Rather than commenting it out every WooCommerce upgrade, ask WooCommerce to fix it so you don't have to. ;)