I went shopping after that initial post and, given the odd way the brain works, thought, in between aisles: you assumed it would just set up the right directories like Windows, idiot.
I was right. I just had to create/direct the right directories. Same with Wordpress which, unless you really want to get your hands dirty, needs to be in the same directory as the index page you produce. And you need to understand that directories work on the /home/mywebsite/public_html/mt kind of format, nothing so simple as an extension of your domain name, and certainly not what you see in your browser window. All of this is doubtless obvious to people around here but for newcomers it will, I hope, be of a little use. Anyway both work now though I'm not using them. I actually run two blogs on TypePad and want to transfer them, if I can manage it, to MT here, where my main website is (which uses some very interesting software called Effective Site Studio - you can see my cack-handed results at www.davidhewson.com, which reflect my abilities, not that of ESS).
For anyone labouring over the TCH instructions I should point out they are out-of-date. You will also need to make the right files executable before you point your browser to them. You need to understand the database set up correctly. And in Wordpress you need to delete some extra carriage spaces at the end of the admin file. Otherwise you just get error messages.
Some of this open source software is amazing but the idea it's 'free' only applies, as someone once said, to people who place no value on their time.