If you are specifically after JE's Quadrophenia tone, I would avoid too much drive - he was using a very clean, warm tone at this time as a reaction to his years of treble. I would suggest a valve amp or simulator but to be honest I don't even think that is strictly necessary - JE might have been using solid-state Sunns at the time. I use my Leeds as it's always on, but I turn down the drive and treble quite a bit.
I would avoid the VT Bass for JE-type tones, it has a very different character.
I use the Leeds as a preamp, have done for years. I don't think the demo video above does it justice at all - at least not for JE-type tones (using a Jazz bass for the demo didn't help either!). I'm guessing they're using the sample 'Leeds' setting from the manual which is a bit OTT. It really doesn't need loads of drive to achieve the Leeds sound - when dialled in correctly it does it remarkably well. I'm very pleased with it!
I wish I had some idea of how to upload a video!