Just thought I'd update on this thread...
I decided that the electrolosis method left a lot to be desired, the results were completely random and resulted from removing all the verdigris to barely touching it, to coins looking almost no different to coins going yukky and shiny. So the majority of the coins are pretty much uncleaned other than being left in olive oil for a while and a general rub to get the dirt off.
The story behind the coins? I live in a heritage listed house in a national park - in pre-decimal days, the house dwellers were responsible for collecting a penny from visitors to the park. A bucket sat beside a hedge and visitors would throw a penny in the bucket. Some coins didn't make the bucket, some ended up in the hedge and couldn't be retrieved. This hedge has since been removed and my children and I ran a metal detector over the hedge area and found over 80 lost coins. Mostly pennies, few halfpennies and a threepence bit.
I have framed most of the coins with one lot now being kept in the information centre in the park with a little story about how they got there. Another lot are framed and are in the house - as far as I am concerned, they belong to the house and if we move, the coins will stay here with the house or be handed over to the park. The rest of the coins have gone up to Old Goverment House here in the park and are being used as part of a display.
I will get photo's at some point of the end results. Thanks again for all your help.