http://www.redexpress.co.uk/store/s1...8/details.aspx

http://www.redexpress.co.uk/store/s1...)/details.aspx

I used a Hylomar sealent, but im pretty sure that mine actually sets, so you might want to try the first one. You dont have to buy them from there, they are the first results i got on google lol, but they would be upto the job.

As for the gasket sets, i would go for the £33 ones in the first link.
That is all you need to renew the rocker cover gasket.

All the other gaskets would create you alot of un-necessary work, especially if your existing ones are ok.