A wonderful car. My dad got more than 300,000 miles out of his 190E 2.6 auto, then sold it to a taxi driver. A 1992J example may have a catalytic converter and it will have if it’s a 1992K, so no escaping the MoT advanced emissions test. If it's a lovely car, £1,500 would not be too much. But this sort of deal over an older car is more about gut feel and finding a mutually acceptable deal. He might take £1,000. He might take less. Though to be fair to both of you I would try to start the negotiations at £1,000. (Glass's Guide to older car values puts a 92J auto with 126k miles at £735 from a dealer or £535 bought privately and a 92K auto with 23k miles at £785 dealer, £585 private.)