I was in the same boat last week ( but not with an easy cooker ) Am not a roast type of gal so had no idea what to do with what I'd bought.

Luckily the M&T Roast Beef I'd bought had instructions on it! Don't know if it makes a difference the cut but it said to do the 1kg roast in a fan forced oven at 180C (so 200 for non fan forced) for an hour then pull it out cover with foil and rest it for 15 minutes. B I though it was a little too pink in the middle for my liking) so I'd do it for another 10 minutes if again. I have a slow cooker but no idea how it works - try googling easy cooker's brand and see if you can get the instruction manual?