The British-English adjective oojah-cum-spiff means fine, all right.

This adjective is perhaps an alteration of the noun oojah capivvy ¹, after:
– the preposition cum, borrowed from Latin, meaning with;
– the adjective spiffy, meaning smart, spruce.

¹ The noun oojah capivvy denotes a thing whose name the speaker cannot remember, does not know, or does not wish to mention—synonym: oojah.

The first two occurrences of the adjective oojah-cum-spiff that I have found are from stories by the English author Pelham Grenville Wodehouse (1881-1975), who may have coined it—these two occurrences are as follows, in chronological order:

1-: From Chapter VII of Leave it to Psmith, published in The Saturday Evening Post (Philadelphia, Pennsylvania, USA) of Saturday 24^th February 1923:

“It will be dark, I suppose, by the time we arrive,” he [i.e., Lord Emsworth] said regretfully; “but the first thing tomorrow, my dear fellow, I must take you round and show you my gardens.”
“I shall look forward to it keenly,” said Psmith. “They are, I can readily imagine, distinctly oojah-cum-spiff.”
“I beg your pardon?” said Lord Emsworth with a start.
“Not at all,” said Psmith graciously.
“Er—what did you say?” asked his lordship after a slight pause.
“I was saying that, from all reports, you must have a very nifty display of garden produce at your rural seat.”
“Oh, yes! Oh, most!” said his lordship, looking puzzled.

2-: From Jeeves and the Impending Doom, a short story published in The Strand Magazine: An Illustrated Monthly (London, England) of December 1926:

“All you have to do,” I said, “is to carry on here for a few weeks more, and everything will be oojah-cum-spiff.”
Bingo barked bleakly.
“A few weeks more! I shall be lucky if I stay two days.”

The following are two texts in which the adjective oojah-cum-spiff is used without reference to P. G. Wodehouse:

● From the Brooklyn Eagle (Brooklyn, New York, USA) of Saturday 16^th January 1943:

West Point Drillshed Break for Dodgers
Use of 400 by 200 Field House Can Give Flock Training Edge Over Other Ball Clubs If Weather Turns Bad in March

By TOMMY HOLMES
Chaps yesterday would ask me where the Brooklyn Dodgers had finally decided to do their Spring training. I’d answer, “Bear Mountain,” and they’d laugh. I don’t know why. Branch Rickey’s setup probably is as good as any other club’s in accordance with the wartime restrictions the major leagues laid down for themselves. And may be better if weather is bad in the latter part of March.
[…]
So far as the boys are concerned, I see only one difficulty. Bear Mountain isn’t a town, you know, and I don’t know what the athletes will do for their evening movies, even though they’re only 45 miles from Broadway. Transportation being what it is, they’ll be pretty well chained to the inn and ten-cent poker can get pretty deadly in three weeks.
Otherwise, everything seems oojah-cum-spiff. The Palisades Interstate Park officials are happy because the ball club will take in some of the slack between Winter skiing and Summer outings. Maj. Gen. Francis B. Wilby and Col. Biff Jones, the old Army football coach, were most cordial in extending the use of the West Point facilities. And Branch Rickey is dee-lighted. He has his indoor batting cage.

● From Hongkong: let our people go, by Bernard Levin, published in The Times (London, England) of Saturday 15^th September 1984:

Let us say for the Foreign Office and Sir Geoffrey ² what can be said for them (while noting, however, that they have not said it for themselves): Hongkong would be militarily untenable in the face of any serious attack by China. Since that is so, and since Britain in any case considers herself bound by the original treaty to hand back the territory to China in 1997, we must perforce sleep through a dream of “negotiations” which will lead to an “agreement” by the terms of which China will be “bound” to allow Hongkong to go on much as it is now for 50 years after the cession has taken place.
[…]
[…] Let us assume, lest the argument should die right here, that the men who are ruling China in 1997 will have the same attitude to Hongkong as is held by its rulers today. […]
Then everything is tickety-boo, hunky-dory and oojah-cum-spiff? Well, only if Sir Geoffrey will answer one more question that his department would consider in the most deplorable taste (and for good measure inopportune): what communist country does he know which, having incorporated within its borders some five million people of another country who have previously been used to freedom of speech, worship, political association, travel and economic activity (to name but a few) has permitted such conditions to prevail for one year, never mind 50?

² This refers to the British Conservative politician Geoffrey Howe (1926-2015), who was Secretary of State for Foreign and Commonwealth Affairs from June 1983 to July 1989, under Margaret Hilda Thatcher (1925-2013).