It's also worth noting that in South Kintyre, the Tory vote in the 2012 election was likely to have been so high because the guy standing for them has been a councillor for years and is pretty popular locally. He got in at first by standing as an "independent" (like a lot of Argyll & Bute councillors who suddenly became "independent" in 1997 for some reason, can't think why) and then switched back to being a Tory in 2007 and has carried the support with him. It's unlikely that any other Tory candidate would do as well as he does in a council election in South Kintyre. In fact, they couldn't even get a properly local candidate to stand for them yesterday as the candidate chosen lives in Lochgilphead, 55 miles away. Hopefully last night's result is a good indicator for May but I wouldn't be putting the mortgage on an SNP win in Argyll on the back of it.
I'm sure John would've walked the by-election anyway and will be a good representative for the area, just in case the above sounds overly negative. Just trying to be realistic.