SSD
I somewhat doubt they meant that and I wonder if there's been a misunderstanding.
On one airline I know of on the line the V1 (amongst other things) is calculated by entering weight and other factors, as you put it, into either a computer program or by reference to a (thick) book which contains a page for every single runway on the network. If you're using the computer you enter the runway identifier and entry point, not the length into the "computer", if using the book you use the page appropriate to runway and entry point. In neither case do you as the pilot, actually enter the numeric runway length in feet or metres, since the "computer"/book has that inormation so it is a value most assuredly involved in determining the value of V1.
I suspect that is what your Big Aeroplane pilots were driving at ( at least I hope that was what they meant, otherwise )
No, our conversation was quite specific and 'runway length not a factor in V1' was the whole basis of our discussion. In fact it was one of these ex-BA captain chaps who came up with the Salt Flats scenario to illustrate that V1 can be meaningless in some circumstances (i.e. you may be OK to stop when really at any point after V1 you should fly. There's a judgement to be made if it happens).