transportation from Heathrowe to Moreton-in-Marsh

A) National Express bus to Reading rail station, then direct train from there. www.nationalexpress.com

B) Heathrow Express to London Paddington station and change there to the next train. www.nationalrail.co.uk

Train and bus schedules will always ask for which arrivals terminal at Heathrow.

Thank you for your information. If we take the railair bus to reading, is it far to the train station?

The RailAir coach stops in front of the station at Reading.

If you are arriving at Terminal 5 taking the Railair coach will be quicker and cheaper than back tracking into London. From Terminals 2/3 time is a wash but will still be cheaper. The Railair coach does not visit Terminal 4 though so would mean a change.

Buy Railair tickets between 2 and 3 months in advance from www.railair.com for the best price - especially for a return ticket.

Take taxi from Heathrow to Slough (7 miles) train station, then train from Slough to Moreton-in-Marsh it's a 1 hr 20 minutes.

Fairly frequent buses to Slough too.

a taxi to Slough from Terminal 4 then a train to MIM is very easy and the least expensive. I did not check the bus to Slough, but we will be very tired after a flight from the west coast and a taxi that meets us is welcome. Thanks for the suggestion
katharine

Terminal 4 is very much the poor relation of the terminals for public transport for points other than London itself, mainly because of its somewhat isolated position compared with the others. If you are arriving here then taxi quite probably is the best to get somewhere better connected.