No. Should I have to when I've just SFTP'd everything over?

Unless you've also copied the vendor directory over, you'll need to do that as well. Laravel manages its dependencies through Composer, so as a result all of it's internal components are stored in the vendor folder.

Yeah vendor went across as well...

I'll install composer on Plesk tomorrow (can't SSH from home IP) and run it. Thanks.

OK, so I got this working. I installed composer on Plesk and ran composer install as citricsquid suggested.

Thanks!

Although I was still pretty confused as to why I should need to run install again since the site was deployed via SFTP and everything (including the vendor dir) got uploaded - or so I thought...

I had failed to notice that the vendor dir is listed in the supplied gitignore, and since I ran deployment from the git repo on beanstalkapp.com it wasn't uploaded. My bad.

@ollie-new Same situation here using Beanstalk, thanks for your comments and help, mine was solved too.

thanks i solved my problem !!