One of the ‘duh’ moments that now seems blindingly obvious. The received wisdom to change the default search engine in Edge is to navigate to Settings | Advanced Settings and pick one. However, the one I wanted – Google, wasn’t there. On previous devices it wasn’t there and only appeared for selection after an indetermine period has passed which could have been days or weeks by the time I’d bothered to look again.
I’ve just realised what’s going on, the fault being me the stooopid user. No alterative search engine options will be offered until you visit the serach page within your normal browsing activity i.e. Google wasn’t offered, I navigate to Google in the browser, look in Advanced Settings and there it is. Doh!