Best advice is to at minimum ,follow Manufacturers instructions. Personally I would go one step further and use Heat resistant flex. reasons being that on some built in ovens a fair amount of heat can be expelled through vents and if your cable is not carefully routed it can receive this heat full on. T&E although commonly used in this application is not the correct type of cable for final connections to appliances.
I can see why you suggest the second option could be best in relation to the provision of a 10a fuse for the oven ,but in practice if the oven where to blow there would be a 50 -50 chance of the F.C.U. 13a fuse blowing anyway so there would be no guarantee of fault discrimination.
Thats a bargain price , I can see a few forum members making their way to their local branch tomorrow....there are three branches fairly local to me so may bag a few myself . Ta !