OK I finally circled back on this as I expected issues might arise on the reinstall. As noted above, I'm using DW CC 2014.1 not 2015. Downloaded, installed DE 1.21 and reopened DW.
1> I got the attached error repeatedly by just opening DW
2> I clicked it away just to see if my presets were still there. Activated DE and when I opened both Google Pro, the multiple locations box was still greyed out and then I opened CSS Menuwriter, it showed my presets but when I clicked on them i got "The database connections for this content preset do not exist in this site. Please create the following connections to use the preset GSCsql." GSCsq.php does exist already in my/Connections folder from when DE 1.2 was installed and working before.
3> Just for info, I tried opening DA and it could not find the SQL connection and then started kicking out the same error attached. On retry, it won't even open.
I did backup the DW/Configuration folder as you suggested before the install if that helps.
Help please - I'm stuck as even without accessing WA products DW is popping the attached error and preventing me from working.