This is fascinating stuff, especially on the overall trends in Christian/religious identity and in the specifics of identifcation (or rather non-identification) with the Scottish Episcopal Church. The six different lines (you made up your own category here) that seem to contain the Anglicans resident in Scotland are (in numerical order):
Church of England 66717
Scottish Episcopal Church 8048
Church of Ireland 2020
Church in Wales 453
By far the largest of these was Church of England: which does not exist in a separate form in Scotland and has not since 1986 when St Silas in Glasgow joined the Scottish Episcopal Church. The 'Episcopalian' and 'Scottish Episcopal Church' lines probably add up to something like the 'actual' SEC church membership, give or take a few thousand. Kelvin has a much better researched take on it, but essentially the English Anglicans in Scotland don't stampede into the pews of the Anglican province in Scotland.
And why would they?
The Church of England is a much, much broader church than the SEC, with a strong evangelical wing, a catholic wing, a large progressive/moderate rump and all the rest of it. Why would an English evangelical go along to a service which looks like a catholic mass? Or why would a moderate, middle-of-the-road Anglican travel an extra 15 or 20 country miles to find an SEC church when a good welcome and an active Christian community might be there on their doorstep, in one of the Churches of Scotland? (although their stats are alarming in the census - from scientific observation it would appear that the Church of Scotland is in danger of creating a religion-free Scotland!) The same issue applies to anyone who might wonder about wandering in and meeting us.
The issue of branding really, really matters. But so does the issue of what the product is like, once the brand has brought someone in through the door. And that is where we will find ourselves working hard to understand what we are today. A snapshot, from a recent-ish conversation with a person (who goes to no church) in my patch.
Her: "What does 'Scottish Episcopal Church' mean?
Me: 'Well, 'Episcopal' means that we have bishops, and are one of historical churches in Scotland, dating back to...'
Her: *glazes over*
Me: 'We are a church that thinks all people are valued by God, regardless of gender, race, sexuality.'
Her: 'I might come to that.'
Me: 'You would be welcome.'
She's been a couple of times, to a midweek: She looked like she found it all rather odd. But I wonder what she really found...