Thanks for that Andy,
My battery boxes are not yet here [from China] but I am not expecting them to have resistors [i have never yet fitted a resistor to anything myself].
Until I read your comment I did not think about the Xmas LEDs as having resistors in them. I have another unopened box of Xmas LED lights, waiting for a decision as to how to use them.
I have seen the sales on ebay for things like street lamps [LEDs] and their comments that they must be maximum 3 volt [but they don't say how many lamps per each 3v - but with no mention of resistors].
I have also sent for some LED street lamps, again from China, So when they arrive I shall try to suss out the resistor situation, and then wish myself luck.
Thanks again Andy.