Wherries brewed with kit yeast probably stick because of the miserly amount Muntons supply in the packet. You might be lucky and it doesn't stick, you may not.Woodfordes (and some Forumites), might disagree, but fermentation is known to regularly stick at about 1.020 using the kit supplied yeast. This happened to me twice and I never figured out why. I had to rush out to Wilco's for a sachet of their GV12 yeast. Since then, I've become a bit paranoid about using the supplied packet. Also, you get almost double the quantity from Wilco's - 11gms. GV12 also seems more 'tolerant' and the finished gravity is usually lower and therefore ABV will be higher.
Woodfordes - don't get me wrong.!!! Your kits are my favourites! I buy more of them than all others put together, but your yeast...I can't get on with it.
This is a Wherry I pitched last night using a cultured up SN 1698 yeast. Took the snap a few minutes ago. (Tried a short video but it wouldn't load.) I've never seen this activity from a kit yeast.
My experience with the 1698 yeast is that it is fiercely top fermenting so much so that it rises to the top rather than stays in the brew. I found I had to turn in the yeast to keep it going, or else it would have stalled. Look at posts 30,31 and 32 in
http://www.thehomebrewforum.co.uk/showthread.php?t=60341&highlight=1698 if you are interested.