Hi, by car Gosport is about 2.5hrs from Evesham, so at 50 I reckon it would be about 3.5hrs.
If you decide to come best way is onto A34 to Oxford, then A44 through Chipping Norton, Moreton-in-Marsh towards Evesham, turn right onto A46 for 1m then right at next roundabout towards Badsey, then 200yds on right turn right into drive with large green sign RB James.
cheers
Paul