Can storage be used as come & go as you

Hi we currently park our panel van conversion outside our home on the road, which works fine where we are at the moment as the roads are nice & wide.

We are looking into moving, downsizing our home to allow us to spend more time out in the Milliemobile less time at home, as we have lived all over the UK  over the years not yet sure where we will end up but thinking about parking the van when at home I realise a lot of places won't have the outside space and wondered if we could use a storage facility instead close to a new home, somewhere we could come & go as we please, paying for whole year but allowing us to take the van out whenever we want, can anyone advise if they know of any storage places that can be used in this way for a motorhome/panel van conversion.   

Location not important at the moment just an idea of if such an arrangement is possible, but more than likely to end up in either, Portsmouth, York  or coastal Devon & Cornwall as these are my favourite places.