Top Rump

I would always roast any beef joint in the oven. I usually cover the tin with foil, until I want to add the vegetables to roast round the joint. Timings depend on how big it is.
I use a meat thermometer to tell me when it has reached the stage of cooking that I want. We like our beef medium/well done.

I wouldn't cook top rump in a slow cooker, only stewing beef or perhaps brisket.

The butcher where you bought it should be able to advise if there aren't any instructions with it.

I started to answer then looked online and there are so many different ways to cook it, perhaps it would be best if you google it and decide what you would like to do.

All of them suggest 'resting' it for a while afterwards which I think is essential.

Hope it turns out well.

In the oven 100%

Roast it.
In the middle of the oven, in appropriate roasting pan, best when a little pink in the centre.Rest it after cooking for 20 mins wrapped in foil before carving.

Top rump isn't the easiest piece of beef to get tender. Comes from a hardworking part of the animal. Needs a slow oven, addition of a little water to pan, and covering with foil. Will be tasty though.

In the oven, covered, long and low. Enjoy!

Thank you so much everyone. I'll let you know how I get on

I roasted a piece yesterday. In the oven, low heat Gas 2. Rested it for about 20 mins while I cooked the yorkshires. It was lovely, don't have a roast dinner often these days so we enjoyed it.

Rub the fat with a mixture of mustard powder and flour - then roast, makes a yummy crust

I have some 28 day matured silverside from Aldi to cook, don't often do it (being veggie myself). Last time I did it in a roasting bag, and cut bag away for last 20 minutes. It was good. Can't remember how hot I did it sadly.

It's best to ask a butcher at the shop where you bought it, or, the supermarket fresh meat counter.