Roast beef - how long?

[Trinaj]

How long would you recommend roasting a forerib of beef? (3lb) for medium / well.
I looked at Delia's and she recommends 15 mins per lb + 15 mins extra. This doesn't sound very much to me, what do you think?

I would cover the roasting tin with foil and put in in on 4 for an hour, get it out and poke about a bit. The foil stops it going brown and shrinking. Then put it back in for 30 mins at a time. It shouldn't take more than 2.5 hours I wouldn't have thought.

also if u rest it for 20 - 30 mins after cooking it will still be cooking inside and gives the juices a chance to settle back into the meat so you don't serve a shrivelled welly with your yorkshire puds!