Thanks for the reply above.. seems best to find out what its giving out.. been also thinking if its a fuel release or fuel pump issue, and also other prob's get a felling of a sticky accelarator in cold weather and possible a clutch prob in reverse as backing up every so often the battery light flickers like the car was just about to cut out..
Might be an electrical fault by the sounds of things. Might be a slight missfire causing the lack of low down power Would defo get it on a RR and get it diagnosed if it doesnt seem right. As they will be able to see exactly what everything is doing and see where the fault is.
I myself have spent a fortune trying to diagnose a problem myself then not sorted it, got it diagnosed by a tuner to find out it was a cheap repair of something that I just missed.