Oban Divers campsite is now called Roseview Campsite. Fantastic place very peaceful.
Roseview Caravan Park and Campsite Oban Argyll Scotland
I don't know if the Tyes still own it or indeed if Dave is still around (hope so) I haven't seen him in about 10 years, really nice guy.
Another site on the coast is Oban Caravan and Campsite
I've stayed at both and both are good. Oban Divers has a special place in my heart
With both of these you may be able to hire a mooring at Puffin Divers for your trip.
Puffin Dive Centre - Scuba Diving, Commercial Diver Training
Or at Dunstaffnage Marina
Dunstaffnage Marina Oban
Failling that you could launch at the Port Beg slipway (free) next to the RNLI station in Oban.