The government body, which owns and maintains 400 historical sites in the UK, has divided the review into three ‘lots': a national account, handled currently by the Bristol office of Grayling; nine regional accounts; and a special projects roster.
The national account focuses on handling comms for 20 key events commemorating England's past, and several major EH properties such as Hadrian's Wall and Stonehenge.
Last year, EH acquired the 17th-century Grade II-listed Abbey Inn in Yorkshire, the first pub to be owned and run by the body.
‘Most of the nine regional agencies are approaching the end of their contracts with us and the national account is also up next year, so we thought it made sense to overhaul the whole lot in one go,' said EH senior comms manager Rebecca Milton.
The special projects roster includes work on initiatives such as last April's launch of EH's self-catering cottage holidays.
Pre-qualification questionnaires are currently being sent out to agencies, after which a brief will be drawn up, followed by pitches and interviews.
‘It is likely to be a long process,' said Milton.