This series was the first series in which guest mediums joined the team during the investigations. This took some of the pressure off Derek Acorah who had been the only medium in the first three series. The main guest mediums involved during this series were Salisbury native Brian Shepherd, David Wells and Scunthorpe's Ian Lawman. Series five commenced on 14 September 2004. It was preceded by a 3 night "Most Haunted Live!" investigation advertised as a countdown to the series. Phil Whyman was replaced with (although he recently returned on the Live shows as a studio expert), then semi-regular, Ciarán O'Keeffe. Originally O'Keeffe viewed the footage recorded during the investigations and analysed it, putting forward his own views and opinions, which usually included suggestions as to other possible causes for the phenomena encountered. He shared this role with his colleague Matthew Smith who frequently attended the early "Most Haunted Live" events. Following the departure of Phil Whyman after Series 4, O'Keeffe began to join the team on location. Yvette's brother Rick Fielding also left the show at the end of Series 4. At the end of Series 5, Antix Productions began editing the series in-house at their own production offices. Prior to this, post-production had been completed at 422 Manchester. As a result, the series lost its original editor who had worked on "Most Haunted" since the first episode and all of the vintage film composite effects which resulted in a considerable change to the editing style and look of the programme. For series six, beginning on 22 March 2005 with an investigation of Bodmin Gaol, David Wells became one of the main mediums alongside Derek Acorah appearing in every episode. This was Derek Acorah's last "Most Haunted" series owing to the controversy he was involved in during its production which cast doubt on his ability to perform his role. As such he did not appear in the final episode at Sinai House. The number of episodes for Series 6 was originally intended to be eighteen, with the last eleven being part of Series 7. Due to Acorah's departure, the series was extended. This was the first series in which the team conducted 24-hour investigations over in the USA. Acorah didn't return for the show's finale at Sinai House when David Wells was the main medium. The seventh series began on 1 November 2005 yet only ran for six weeks, shortened from an intended nine. Two of the final three episodes (at Bamburgh Castle and Chambercombe Manor) were broadcast at the end of Series 8 and the last, at Spitbank Fort, was broadcast as special on Boxing Day 2006.