Before setting out on a long journey, I think it's highly advisable to stock up on provisions. Not just because train buffets can be unpredictable, but stock levels are also notoriously fickle - it's not unusual for them to run out of sandwiches within minutes, it seems to me - and they are quite pricey for what you get.

So this M&S Simply Food is a compulsory stop for me on my regular visits to see the folks in Wales. I love their avocado and spinach sandwiches with mustard and pine-nuts, and the chocolate flapjacks. As with all M&S stuff, it's a little pricey, but it is reliable on quality, and they are making a big effort these days to be more environmentally aware, and to purchase fairly traded goods. Staff here always seem friendly, and it's less frenetic than the adjacent Sainsbury's.

This branch is also good for buying fresh flowers to present to your hosts at the other end, and with generous opening hours, worth knowing about if you are stuck for provisions late in the evening.