It's the small one they do in Asda, it weighs 700g.
How long and what temperature approximately in a fan oven? I normally roast pork loin and comes out great but forgot to defrost the one I had in the fridge so I went out and bought pork shoulder. Thanks in advance.

It tells you on the back of the label. I've one in my freezer and I think it's 35 mins per 500g + 35 mins if I remember correctly. It also mentions 15 mins resting time but I don't leave mine that long. Generally takes about one hour and three quarters for me on 180 in a fan oven. Until not very long ago they were £6 for 2 , now they are £4 each.

Shoulder can be a tough cut so I always do a low and slow for about 3-4 hours on a bed of root veg. Then, when the meat is tender I just put the baking tray on the heat and add a bit of stock to the veg, bubble it up on the stove top, mash the veg into the stock and then sieve it for a lovely gravy.

Thanks, yes I saw the cooking instructions but had problems with a silverside beef joint following their instructions (it was like leather) so I thought I would ask.
I hope it turns out ok. I said I had a pork loin that I forgot to defrost, but wrote in the fridge instead of freezer oops.
I didn't buy another pork loin, which I know how to cook successfully, because it always leaves me with lots of leftover meat and I already have a bag of leftovers in the freezer to use at some point, so I went with the smaller shoulder joint that should be more than enough for two people.
They had the small loin joint (about 700g) some time ago, I couldn't see it today.

Bib - I used to have the exact same problem until I realised silverside should be slow cooked for hours - now I don't bother with the instructions and I just cook it on low for at least 6 hours and it comes out beautiful and tender.

20 mins per lb (I'm old money...) plus 20 mins on 180/170 fan. Shoulder I find is better to roast as it has more fat on it. Also gives better crackling. Just make sure you score the skin and tub in plenty of oil and salt.

Generally these days I just shot it in the slow cooker with a bit of stock and seasoning rub and leave it in there until i'm hungry. Could be 4 hours could be 8

Supermarkets should be pulled up for selling tough cuts of beef as 'roasting joints'

Boyfriend said it was nice. I ended up roasting it at around 160 degrees for about 2 hours. It wasn't falling apart but that's ok because I wanted to be able to slice it. It wasn't tough at all and moist (guess the fat helped). Thanks again for your answers.

Totally agree!

Me too, that's why I was bought silverside that time: it was labelled as a roasting joint.