yeast conversion

I'm looking for a Wyeast equivalant of White Labs #WLP002
I've done a search and found it to be..... Special London 1968
My question is, What would a second choice be? Just in case my LBS doesn't have the 1968
After some reading I think next closest would be London Ale II 1318
I'm not sure though and figured I'd ask the Pros here
I'm brewing Yuri's Thunderstruck in extract
Thanks,
Pete

According to http://www.mrmalty.com/yeast.htm - they are both the same strain (at least they both come from Fullers and they are English Ale yeast)

Here: http://www.wyeastlab.com/hb_yeaststrain.cfm you can compare strains. The 1318 looks like a possibilty.

I'm getting ready to brew with 1968 tomorrow morning an ESB on an extra special day.

The 1968 says this in it's description. " A thorough diacetyl rest is recommended after fermentation is complete".
What does that mean?
I tend to leave my brews in primary for at least 4 to 5 weeks so I don't think it will be an issue, but I would like to know what it means.
Thanks,
Pete

Some yeast produce noticeable amounts of diacetyl which is a compound (ketone) that is a byproduct of fermentation. This is said to give a buttery flavor which is undesirable most of the time. After the yeast have consumed most of the fermentable sugars, they will continue to consume the diacetyl and thereby lower the levels of diacetyl to an undetectable level.

So in other words, let the primary go all the way and continue to let the beer ferment (in secondary) a good week or longer after primary fermentation is mostly complete. Force the yeast to eat the diacetyl.