A British-based real estate and investment company has made a tentative, uninvited bid for the last publicly traded company of the venerable Fairchild aerospace group.

Mountleigh Group PLC, headed by U.S. financier Nelson Peltz, notified Fairchild Corp. of Chantilly that it intends to offer $10.25 in cash and $4 in stock for each share of the company, Fairchild said. The offer appears to be worth about $235 million.

The offer for the remaining entity, which manufactures aerospace fasteners, comes 21 months after the Fairchild giant was purchased and broken up in another takeover.

In its announcement of the offer yesterday, Fairchild described it as "highly conditional," depending on Mountleigh arranging financing and possibly getting various approvals.

Fairchild said its board would make a decision if and when it was presented with a more definite proposal.

Fairchild was bought by Cleveland-based Banner Industries Inc. in 1989, following a lengthy takeover battle between Fairchild and the Washington-based Carlyle Group, which had made a hostile offer for Fairchild.

Banner subsequently sold Fairchild's space and defense division to the French aerospace group Matra, then last November merged itself into what remained of Fairchild.

The company reported sales of about $700 million in the fiscal year that ended June 30. Since then, however, it has spun off part of its business. It reported net income of $1.5 million in the year ended June 30.

Fairchild remains heavily in debt, having taken on obligations that Banner acquired in the 1980s during a growth surge. Fairchild had about $573 million of long-term debt on the books as of Sept. 30.

Mountleigh is headed by Peltz, who emerged as a major player in the takeover business in the 1980s. In many transactions, he worked with Michael Milken, the junk bond financier who later pleaded guilty to securities law violations.

As head of Triangle Industries, Peltz bought National Can Co. in 1985 and sold it five years later at a large profit.

News reports in London have said his company was on the lookout for another takeover target.

A Mountleigh official, reached in London by telephone, yesterday declined to discuss the proposal.

Fairchild stock yesterday rose 50 cents a share, closing at $10.25 in trading on the New York Stock Exchange.

Fairchild also announced a program to retire some high-interest debt that Banner took on in the 1980s. Under the deal, Banner will pay a major holder $700 for each $1,000 of debt, one-third in cash and the rest in a 14 percent note, and offer the same terms to other holders of the debt.