The ones that I have seen are just stamped by the solicitors stating "Certified to be true copies of passport of Mr Fred Bloggs". This is done on every page and then signed and stamped by solicitors.
The reason why I always say have every page stamped including blank ones is that I have known several people to be refused because they did not submitt pages of refusal stamps of countries they visited, but submitted all other pages. I am not saying it happens all time, but to cut teh chance of being refused, I stamp every page, so the ECO is fully satified that he has seen every page of teh sponsors passport.
I dont think you need to go the length of having the red seal and wax job done on such things. You will pay extra for that type of service
Yes not all solicitors are notaries. Infact they are very few about where I live. Justice of the Peace certified copies of your passports will not be accepted as well