I found Warranty Direct utter merde on our Astra. They cap labour rates to silly levels and generally wriggle out of anything.
Be aware that extended warranties are insurance NOT proper warranties – each claim has a big excess so only to be used for big stuff.
I've chosen not to extend ours on the 335d because IMO, it's not worth it. £450 for the warranty with £250 excess – so if anything does go wrong, it needs to be over £700 to be worth getting the warranty for!! **** that.
Yes if the engine goes pop, then oh darn (looking at £10k for a new one) but I plan to keep it regularly serviced and oiled up. Not one has failed so far.