Running AVG 7.5 Free edition; seems grisoft have now started to advertise their AVG Pro version for us to 'upgrade' to by presenting us with an unrequested and unwanted ad page with the invite TO upgrade; have other avg FREE users on here had a similar 'experience'? and is this not stooping to the level OF the spy companies by utilising such methods as sneek advertising ?

I would not call it sneak advertising, annoying as such nag screens might be.
AVG isn't the only one. I've several do so by now, though perhaps not as intrusively as a nag screen.

Sanity check: It's the price to pay to be able to use a free version of a good product for nothing while people who pay actually end up supporting it.

Check if there is an option to disable it. Or pay.