Thank you everybody for your replies and the gentle chastisement, as well as the support of those who have been there before. The situation isn't as straightforward as it seems. I only work part time - 3 shifts a week. I have an elderly disabled husband and another dog (we have always had 2 or 3 dogs at a time). I thought that with my husband being there all day, and the other dog, that he would settle. Unfortunately my husband needs to go for a sleep for about 3 hours or more while I'm out and that is when the dog was at his noisiest. We had him for 6 weeks and he became much more confident, started to bark and was learning very very quickly. He was very destructive, though, and my husband was unable to stop him when I wasn't there and if he put him in his crate he would bark non-stop. The neighbour, who is a very difficult person at the best of times, was the last straw. Most of our dogs have been rescue and they have all been fine and have been with us for years. My main mistake was in believing that the dog would be a companion for my husband and curl up on his lap - didn't work out. I know how to deal with separation anxiety but it would have taken time and the neighbour is not a 'negotiable' type of person. Believe me, I am beating myself up about this and I shall be suffering for a long time. I shall ring the kennels regularly to check whether he has been re-homed. He is such a cute little dog that he will be snapped up very quickly I'm sure.

Miranda Luck - as I explained, I know how to deal with SA but because of the neighbour, time wasn't on my side. I have a daughter with a degree in dog behaviour and she offered to take him but she is out at work full time and it would not have been suitable. I cried for 3 days, then I saw him on the kennels' website and now feel so much better after reading that he is in a wonderful foster home. Anyone who is interested can see him on www.hwanimalrescue.org - look under dogs needing homes and his name is Smudge - the little white terrier on a red floor, chewing a ball.
A relative of mine suggested that I look on it positively as if I had been a foster home for him. He was a very nervous and scared little tatty scrap when I got him, with no interest in humans or playing. He developed in just 6 weeks into a confident, basically trained, happy and playful little chap. The kennels said he was like a different dog when I returned him. Nuff said!