i have two in bristol. no problems here

could be a lack of water as bamboo need a lot of water

A bit more information is needed:
What did you transplant from/to (Pots/ground)? If you dug it out of the ground did you get a good rootball? Is it likely that you damaged the roots so that the plant isn't taking up enough water?

lack of water - as its recently been planted/transplanted, it will need soaking regularly, so as its showing signs of distress already, give it a good canful of water around the roots daily, regardless of rain (unless its torrential rain), or leave the hose running on a trickle at the base for an hour or so immediately, then water every couple of days with the can.

Agree with Bamboo, when you transplant Bambo they tend to sulk and can lose a scary amount a of leaves. With lots of watering they tend to recover within a few weeks.

Thanks for all your advice. The bamboo was transplanted from a friends garden 4 weeks ago. It took a lot of digging out as it was well established but we did get a good size root ball with it although I suppose some of it could have been damaged. My husband was putting 2 or 3 cans of water on it every day for the first 2 weeks & it was fine. It maybe had 5 or 6 continuous days without watering (or rain) & that's when the problems started. Since then we've had the hose on it for a couple of hours every day but it doesn't seem to have picked up. It did catch a frost one night & I thought that might be why the leaves had all curled up & gone brown. There is growth & greener leaves at the bottom of the plant. Incidentally a smaller piece of the same plant went into a pot and that is doing fine!

Bamboo also natually lose leaves at this time of year - it will put out new leaves very soon.