Renault/Genii recently employed an outside agent, John Wickham, formerly the technical and operations manager of A1GP, to conduct an efficiency study into the team.
Wickham, who managed the Spirit-Honda F2 team in the eighties and brought the engine manufacturer into F1 in 1983 before Honda did its deal with Williams, was in the Barcelona paddock at the Spanish GP.
Neilsen, who is known to have reservations about the direction the team is headed under Genii management, resigned during the Barcelona weekend but it is believed to be under contract to the team until the end of the year.
It is expected that Alan Permane, another long-term Enstone stalwart, will take on a new role within the team, with Wickham also part of the restructure from the European GP at Valencia later this month. Grandprix.com