hey richard,
I'm not using T3 but I guess these files were created while using the t3 template to combine and minify some files. so when you're using a different template now there shouldn't be a problem to delete that folder at all. however, if you want to be 100% sure before deleting you can simply rename the folder first via ftp (so it cannot be found due to the new path), check your site again and when you see that nothing is broken safely delete it.

hope that helps

Cheers Alex, thank you for the reply, appreciated.

I moved it to a dormant domain i have and renamed it t3-rubbish, no effect on the site so it seems to be a remnant folder not removed with the t3 plugin uninstall and can be safely deleted.

I am finishing off the upgrade on the default Protostar template (Stackideas products just work anywhere out of the box) and may or may not switch to Helix II if the end product looks and works well.

I agree with Mark that frameworks can complicate things unnecessarily and impact on load times although they can help with development until you work out how to do things.

Joomlart support seems to be in a mess based on their latest blog post, I hope their new proposal sorts it out for them.

well, frameworks have pros and cons for sure. for beginners it might be a good option as there are lots of options you can simply click to get started with a design - at the other hand, as mark said as well, after you have set it up you don't need most stuff of it actually so in terms of performance all the unneeded stuff can slow down the site. personally I'm writing my own templates so I have full control of everything but that's of curse not the best option for everyone

but most important good to hear that you're able to remove it and everything's working

Agree with Alex