Photoshop Elements won't recognise Epson Scanner

Mac mini, El Capitan, Photoshop since the 1990s, using Epson scanners, Canon printers.

I've been using Photoshop Elements 11 for ages (years), with my Epson Perfection V550 scanner, no problems.

Recently I bought Photoshop Elements 13, having heard it's substantially better, which it is, but... no scanner.

Go to File/Import and there is no Epson listed. (It does, oddly, list my 'other' machine, a Canon Pixma which I use for printing, but not scanning!). Tried putting the various Twain plug-ins into the 13 support folders (i.e. where they are in the 11 folders), but no makes no difference.

Doesn't matter too much, of course, as I can use Elements 11 for scanning, and 13 for general Photoshop work, but am I missing something obvious?

Thanks for your time.

Allen.