As you are in the UK, I can put a shameless plug for an Ebay seller. He trades under the shop name "the Photographer's bag". I have bought many Nikon items, including a F4, from him and it is always as he describes it. But, look carefully to the photographs for signs of use or cosmetic flows. As an example, I bought a Nikon F75 from him and it is working like a charm as he said, but part of a ring on the mode dial is missing. It doesn't loose any functionality, it is merely cosmetic.
He normally has for sale the 28-80 F3.5-5.6D, the version with the aperture ring for around £42 including P&P. He has now one and you can try to get a discount. It normally goes for £2-3 less.
If you don't mind to go less wide, the 35-105mm F3.5-4.5D is a nice lens and it is an IF model.