I bought my edy 30 privately. Make sure when you test drive it there are no banging or knocking sounds and it pulls smooth and hard in each gear. It shouldn'5 pull to one side under heavy braking. Check to make sure there is no blue smoke from the rear.
Have a good look under the bonnet and check all fluid levels like the other member posted. Open the oil filler cap and check for a white mayonaise like substance. If anything like that walk away, most likely head gasket gone and is expensive to fix. Oil should be a honey like colour and not black and clumpy. Again probably been neglected if you find this.
Check tyre ware and look for rust. They are pretty much rust free however check the door pillars ESP the rear which are known to rust.
Make sure FSH present and check this matches the receipts/invoices to show work has been done. MOT's should be present. Check the log book to make sure the chassis no's match up. You can check this either under the bonnet or front of the dash under the windscreen.
11k seems a bit much for the spec even though the mileage is low for the year of the car. I would go in at 9k and work up. I wouldn't pay any more than 10k max. Good luck mate.