Sorry Douglas, that's incorrect.
Recorded Delivery doesn't provide a tracking facility. (There are prominent notices to that effect in my local post office). Items are carried in the normal mail; it's only upon delivery that they're treated any differently, with a signature being required from the recipient. The number on the 'proof of posting' can be used to view that signature after delivery but it can't be used to track the progress of the item prior to delivery.
It's only the far more expensive Special Delivery service which sees items being handled separately, and tracked throughout their journey.
Jesmond:
The sender of an item ordered remotely (i.e. by post, phone or online) is responsible for getting it to you. If it doesn't arrive it's up to them to pursue the matter with their chosen carrier and, if then necessary, to provide you with a refund or replacement item. Hassle the company to comply with their legal obligation. (If they choose to use a service which doesn't require a signature, that's their fault - not yours!).
Chris