From London by car. Most secure route is M3, A303 towards Exeter. when on the M3 take turn off at A343 to Salisbury, follow the signs to Blandford. At Blandford follow signs to Warminster, then Sturminster Marshall , turning left over the river Stour. At Shillingstone turn left towards Okeford Fitzpaine.
From London by Train.
The the train from London Waterloo to Gillingham on the Southwest Trains Exeter route. Normally select the front 3 carriages (the rest of the train stops at Salisbury). Get off the train at Gillingham, then its an 18km taxi ride to the cottage.