What shall I put in my slow-cooker with this beef?

[BertieBotts]

DP bought some beef steaks from tesco in their 3 for £10 meat offer. We have had them before and they are horribly tough, so I thought they might be nicer in the slow cooker.

I'm not sure what combination of veg etc to put in with them, though, we have:

Tinned tomatoes
Garlic
Herbs
Onions (red & normal)
Carrots
Parsnips
Mushrooms
Stock cubes
Peppers
Sweet Potato
Spices (limited)

Also potatoes but was planning to serve with potatoes.

Have got about half an hour to spend preparing stuff, then will put on for about 6-8 hours. Do I need to brown stuff first, and should I put it on high or low?

I would chop up into small pieces, cover with flour, brown. Soften some finely chopped garlic and onions, add some chopped carrots and parsnips if you fancy, add plenty of water with a couple of stock cubes and let it simmer for hours. This is better with a good thick gravy though so if you have some cornflour to thicken it up so much the better. Serve with mash.

OR

Flour, brown and add whole with some stock cubes, tinned tomatoes, chunky red onions and herbs. Serve with sliced boiled then oven browned potatoes.

Although having seen you posted this nearly 6 hours ago it's nearly dinner time now anyway. Hope it's tasty!

I ran out of time so decided to do it tomorrow instead - thanks for the suggestions