Thanks HI-TEC99. The good news is I have managed to establish contact with Dave and he's seeing what he can do for me. Thanks for your help too 

Oh well, looks like bruteforcing is my only hope, and a thin one at that. Does anybody know if walletrecoveryservices ("Dave Bitcoin") are still operating? Any recent experiences you would be happy to share?

OK, well assuming that I did enter a password but didn't record it anywhere (and have no idea of what it might be), would that mean that the only solution would be to try to brute force it? ? Not looking good is it?

I'm pretty certain I didn't set a password, as when I set new passwords I always copy/paste them from alphanumeric combinations I compose randomly in Word (my passwords file, backed up onto a USB stick), and then copy/paste them as necessary. Likewise with seeds (I still have old seeds in that file btw). I did a search for Electrum in documents and it returned zero, ie there is no trace of Electrum passwords having been recorded anywhere. And I would never come up with a password in my head, hope to remember it and not write it down :-(

Many thanks for this HI-TEC99. You have given a man hope! OK, this so far: I've opened the wallet file and found the word "seed", next to which is a long line of 128 alphanumeric characters. Would this be an encrypted version of the seed?  I understand that, with the seed, I can back up my wallet.dat and delete it, then start Electrum and it'll give me the option to restore from seed. But can I enter the seed in this apparently encrypted form? And sorry for asking yet another newbie question, but I assume there is no risk to the Bitcoins themselves with this process?

I need help, or at least sympathy. Looks like I may well have lost access to all my BTC in an Electrum wallet. They're still there, but I can't send them anywhere as I have no password.
Here's the story. I installed Electrum in January 2016. As I was going through the installation, I got to the display of the seed and the password prompt, but opted not to set a password as at this point I had no intention of sending coins out from the wallet, but simply of transferring my existing coins from an old QT wallet and storing them long-term in the new Electrum wallet. I had assumed (wrongly it would seem) that if at some point the future I wished to send coins I would be then be prompted to set a password which would in turn enable me also to access the seed if I needed to. It seems unbelievable that you can send any amount of BTC to an un-passworded Electrum wallet and lose it forever, without being warned not to do so, nor prevented from doing so. I should add that leaving the password prompt blank when trying to access the seed doesn’t work!

So we have a situation where almost certainly no password was set. If I had set a password it would always have been meticulously recorded in my passwords file (where I compose all my passwords before copy/pasting them).  I have checked my passwords file from January 2016, and tried all possible variants in it without success.

And as for the seed, I would have made no record of it, as I had assumed that this could be revealed at some future point upon creation of a password.

So no password, and no seed. Just the wallet file. Not looking good is it? Is there any way out of here? Or is it finally bye-bye Bitcoin?