I think Preloved is easier to buy from than Ebay. You are in direct contact with the seller, go and see it, haggle on price, buy it and tow it home.[You must be registered and logged in to see this link.]
We are two people only plus little dog and had a brand new fixed bed caravan and after 3 years and impending retirement needed to downsize to save money. We bought a Dandy Designer, a dark blue 2005 one from Riva Leisure, 200 miles away. This one [You must be registered and logged in to see this link.]
To be honest, the older ones were better made and if you look carefully, you may get one with new wheels/tyres, suspension, brakes etc already fitted and this will be cheaper than a newer one, which may need all these items replacing as well.
We only have a sun canopy and underskirt and do like that. However I can see that an awning will provide a lot more space. They appear bigger inside than you might imagine from pictures and are more comfortable than the caravan. Basically, your living space is 8ft x 6ft with the beds as well. The caravan had too many things in the way (wardrobe, washroom etc) leaving only a narrow corridor and the seats only had low backs. The dandy settee is really comfy with a high back.
Storage is an issue but in many ways is easier than the caravan. We use a holdall each for clothes. The Dandy is packed with everything camping related, pots & pans, crockery etc, water containers, porta potti, step, shelf, waste bin, sleeping bags, pillows, EHU lead, TV aerial & mast, TV, heater. The clothes, food & fridge go in the car. Sun canopy, chairs etc all go on top the dandy. Packing & unpacking this way is much easier than the caravan where everything had to be carried in and out.
By day storage can be difficult, but its surprising how nmuch does dissappear in the seats and cupboards. We keep the holdalls on the bed. There is also plenty of room behind the settee when made up. You need to be tidy and put things away, otherwise you can be quickly swamped. The shelf over the cooker holds a lot. The table makes room for the telly and space for preparing food.
When packed the top & bottom of the kitchen remain full as do the seats by the table. There is space under the table for the porta potti.
The fridge is more difficult. Ours is only 21litres which is small and there is no oven.
Good luck in your search and I hope you find a good one.