Recuva Data recovery for videos files does not include file extension mts. I use an HDD Canon Video Camera who's file extensions are mts.
Hi monty, and welcome to the forum.
There doesn't seem to be much in the way of freeware which will recover those HD videos, but "Photorec" (Open Source) appears to be able to do so.
At first glance Photorec looks to be a command line application, but it isn't. Although it doesn't have a "point and click" interface, it does have a "choose and select" structure to it.
I came across an interesting real experience article of Photorec succeeding in recovering .mts files although they don't appear in the list of file formats handled by it. Have a read and you'll see what I mean.
http://www.componentgeek.com/reviews-tips/photorec/mts-file-recovery-review-dont-panic/
Hope that helps.
You can also try TestDisk