Where you planning an evening in Bristol? If not why not carry-on for half an hour and stop at the Tredegar House Caravan Club site in Newport? Litterally just by the M4 and very easy access.
HI DEAN, you could go to baltic wharf caravan club site,its in the heart of bristol,then you could have a night out in bristol walking distance you will have to book its a very popular site. enjoy your holiday in wales ALL THE BEST ALAN P/T