Just a comment on Broadbean's post. You are allowed to modify equipment without invalidating its CE mark. CE marking is to do with selling things not their current condition. If it is not "brought to the market" it does not need a CE mark revalidation.
In the regulations it specifically says you may modify equipment for internal use by your organisation. That is why people in universities linked to hospitals sometimes have honary contracts at the hospital, so they can work on equipment belonging to the organisation they "work for".
Robert
