Thank you to both Skydiver and JimHdk. Your courtesy and promptness of reply are much appreciated. I suspected that I was stuck with these sounds. What is so unusual, surprising even, is that updating my iPhone 5 from iOS 7.0.3 to 7.0.4 did NOT alter the Lock & Keyboard sounds whereas updating my iPad 4 DID alter these sounds. And I have to say they are rather disagreeable.
My wife has just got an iPad Air still running 7.0.3 and is not going to update for fear of a similar experience.
JimHdk, you tended to imply that updating to 7.0.4 shouldn't have changed the Lock & Keyboard sounds. Is it only me or have others had the same experience?
Again, grateful thanks to you both.