From the centre of Oxford head west on Botley Road, past the Elms Parade shops in Botley and take a right onto the B4044 towards Eynsham. About five hundred yards after you pass under the A420 fly-over, look for the bus stops either side of the road.Turn left into the driveway.
Coming from north or south on the A34 Western By-Pass, turn off at the A420/A34 Botley Interchange and follow the signs for Swindon A420 (a left turn if you are coming from the south, a right if from the north). After half a mile or so, take the first exit, sign-posted B4044 Eynsham. Take a right at the bottom of the slip road, pass under the A420 and after a few hundred yards turn left where you see the bus stops either side of the road. Turn left into the driveway.
Follow the driveway past the CBRE building and you will see the Clinic. Drive behind it (into what is actually the front - confusing, but it makes sense eventually) for the car park. If the car park is full, there is overflow parking on the meshed grass area in front of the clinic (well, behind it, but let's not go there again).
Stagecoach run the E1 bus service from Osney Island in Oxford to Eynsham, stopping at the Elms Parade shops in Botley. The Grange Farm stop for the clinic is a few hundred yards past the A420 flyover. Journey time from Osney Island is just under ten mimutes.