"rather long ago" is correct and can be used in written English.
It is often used to indicate that something happened a significant amount of time in the past, but not too long ago. Example: "I remember rather long ago when I first learned how to ride a bike. It was a warm summer day and my dad was holding onto the back of my seat as I pedaled down the street."
By comparison it is necessary to say that if life was ever easy for Daley, if he had a certain momentum that insisted he would be a superstar, it is beginning to seem like a rather long time ago Plainly shaken, he headed off for this morning's semi-finals – when he must improve by three places to join the 12 finalists – confessing, "It was far too close for my liking.
In terms of bone tissue engineering, the use of somatic stem cells was reported a rather long time ago.
A Conservative zealot would have stopped protecting the spending of certain politically important departments long ago, rather than end up with the curiously lopsided Whitehall that Osborne is clearly content with.
Not long ago, rather shallow wells with simple outlines were drilled in oil and gas fields.
The money would be spent for the kinds of community projects that California should have been heavily engaged in long ago, rather than relying on massive, super-expensive facilities to transfer water from one region to another.
Yes, Nick, there is a virgin birth story worth telling -- but its worth is measured not by assertions of what happened long ago, rather by signs of what happens in the telling now.
Or, rather, he made the decision, long ago, while still knowing the alternative.
American teen-agers are no different, in this respect, from the British upper classes, who, until not long ago, would rather be seen dead than not be seen at Ascot, near the Queen.
Putin's late-stage intervention into the crisis could bring about a resolution that, rather ironically, was on offer long ago: Assad in power, for an undefined transitional period, with his regime backed by Russia and Iran.
His job is likely to be divided between two Carrefour veterans: José- Luis Duran may become chief executive and Luc Vandevelde (not long ago the rather ineffective boss of Marks & Spencer, a struggling British retailer), the Halleys' representative on Carrefour's board, the chairman.
You could be forgiven for not sharing my concern: the movie, which follows two sisters, Dottie (Geena Davis) and Kit (Lori Petty), in the inaugural season of the All-American Girls Professional Baseball League, during the Second World War, is mostly fictional and rather mawkish, its climactic game long ago settled.
