?????

It is just as likely that you have not managed to align it properly.

I had to pay a guy to do it for me, it would have been cheaper to get Sky to come and take care of it in the end!

If their equipment is faulty you shouldn't pay anything to have it put right.

Also, if the LNB you replaced was the same as the one in the picture , it's an 11300 LO, so you would need to change the setting in the decoder.

Can you return it?

Sky will do it for free. They own the dish - if it isn't working they will fix it. Ours went faulty (lots of Rain-Fade when it was just cloudy) and they came out the next day and replaced it free of charge (no call out fees or anything). Took the guy about 15 minutes.

I don't know the in's and out's of the MySky box, but on my Freeview satellite receiver, when I preplaced the LNB, the new one was running at a slightly different frequency with respect to the old one, so despite having the correct LNA frequency dialled up in receiver settings I received nothing until doing a retune.

The guys above are talking about 'skew' - when you replace the LNB it has to be twisted on an angle so as to be level with respect to the satellite - not the ground. You need to use a satellite finding website or app to find the correct/approximate skew angle, and once you have a signal, fine tune it for maximum signal strength.

On second thoughts, what makes you believe that the old LNB was faulty?

It is also possible that something else is wrong, hence replacing the LNB isn't helping?

If you do a retune but have not actually fixed the problem, you could make things harder for yourself since you will have 2 problems to deal with - the original fault and no channels tuned in for testing/proving.

Sorting out satellite dish issues is notoriously difficult without the correct tools - do you have a satellite finder similar to this?

The Sky tech's are not expensive. I trouble shot a faulty sky dish for some friends moving into a new house - I discovered that the coax and LNB were both faulty and I couldn't even buy the replacement parts for the cost of the sky call out - so for my friend the Sky tech was the cheapest option.

Have you checked that the L.O. frequency of the new LNB either matches the old LNB or else, have you set the new LNB L.O. frequency into the Sky receiver?

uptoncabling: Don't want to pay the technician fee. I thought it would be a simple replacement

So sky was working until you had a big storm?

You have replaced the LNB with one that has the same L.O has the old one, and your Sky still doesn't work.

I think given the above, it is more likely the dish has moved.

Get Sky out to fix it. They should fix it for free.

Yeah, as above - if the dish is 2 degrees out of alignment you will loose the picture. Dishes aren't at all like terrestrial aerials which only have to be pointing in the general direction of the transmitter. 

uptoncabling: [snip]
Do you know what mysky standard L.O is?

There isn't one - it depends what LNB was installed on the dish. Currently most domestic installs are 10750.