This answers my query, I originally had all our devices using one account for apps and icloud but this 'recents' cache was an issue because my children could see my contacts.
Having removed account settings they still showed which can only be described as poor parental and device privacy on Apples part.
Although the 'recents' deletion is a workaround, this is not a fix and Apple needs to address it as a priority. There are many settings on the units that stop sharing content at the flick of a switch, such as photos. What is the point of restriction and unique accounts if this information is shared.
I've always been a strong adversary of Apple devices but after recent issues I've seriously questioned their privacy over functionality.
Is there an app that I can simply remove all 'recent' items which would save us the time and effort, if they are a contact we're not that bothered anyway.
NB - I'd like to know how the recents were 'shared' in the first place!