The cheaper ones don't have to be in bad condition at all. I saw several otherwise immaculate cars at low prices that just needed your classic 'Alfa Romeo' work needing doing on it (eg. cambelt / variator, bushes, selector plate etc) but the cost of which had scared the owners who had been using franchised dealers. When I bought my 1.6TS Lusso last year, I must have seen about 8-10 cars in the metal (that's how picky I was) over a period of about 3-4 months (I'm patient), as well as countless ads, auctions and telephone conversations with private sellers and dealers. If a seller told me over the telephone that the car didn't have a FASH, I'd politely thank him and move on.
I met a seller with a superb example of a 60,000 mile 2.0TS for £3,750, private sale, owner from new, leather, FAFSH etc where the seller had been brought to tears by dealer costs of fixing classic Alfa faults which would have been relatively simple to remedy through an indie. The 'final straw' had been him spending £350 on discs/pads which had resulted in the VDC error light constantly coming on as a result. The best deals were to be had from respectable private sellers rather than sellers.
Some of the funniest encounters were with people who had overpriced their cars or dealers who insisted they weren't prepared to drop by the price but then dropped it by £1,000 a month later when there were no takers.
There were several independent dealers like the ones you've linked to that didn't understand Alfas, that refused to believe anything about 36k cambelt changes, that cambelt/variator services would cost more than £150 and that a set of spark plugs should cost £90. According to them wishbones, bushes, balljoints, cambelts etc wouldn't need replacing until 100,000 miles.
The cars you've linked to show the 'windscreen prices'. Those dealers won't actually sell those cars for those prices. £4,500 for a 60k 1.6 2001 Turismo? They put a windscreen price on the car way above what its worth, and then if no one bites, they reduce it by £500 two weeks later, then by another £500 and so on because they bought those cars for about £3,000 through auction or trade in. Car dealers aren't generally mugs but there are several small dealers where the penny had to eventually drop in relation to their windscreen price, particularly when they are no takers or potential buyers are coming up to them asking for £500 or 1,000 off. And no dealer will want to be hanging onto a car that's taking up forecourt space that isn't selling. One of the dealers that I visited but didn't buy from eventually admitted that he had overpaid and had to sell at the break even price just to clear the car.
At the end of the day, all the original poster has to do is advertise his car for £4,500 and see if anyone buys it. If they don't bite at that price, how about you offer to pay for his advert in Autotrader for the next month?