I don't think it's an actual Guzzini piece, but this 1970s Guzzini-style chrome mushroom table lamp gets you the look for a fraction of the price.
Saying that, it might be Guzzini. After all, the Italian company made designs like this for high street department stores, so you never know. What we do know is that this lamp has a chrome stem and base, with a shade you can adjust up and down, if I remember correctly (we used to have one similar some time back).
According to the seller, it is in 'nice condition' and 'working order', with with some minor age related marks to the base, while the metal panel on the top of the shade is a bit discoloured. It also requires a new plug putting on the end of the cable.
So not perfect, but check out the images on the site for a proper idea before you bid. £19.99 is the current price.