The phrase "a rather high level" is correct and usable in written English.
It can be used to describe a degree or standard of something that is above average or significant.
Example: "The project requires a rather high level of expertise in data analysis to ensure accurate results."
Alternatives: "a fairly elevated level" or "a somewhat advanced level".
In some ancient civilizations surgery reached a rather high level of development, as in India, China, Egypt, and Hellenistic Greece.
Inefficiency on the power play reached a rather high level for the Devils, who failed with the man advantage six times.
Unsurprisingly, protein samples of C169DHydA1 and C299DCpI both retain a rather high level of H2 release activity (30 80%, Fig. 1).
In Assyria the observation of the Sun, Moon, and stars had already reached a rather high level; the periodic recurrence of eclipses was established.
The judge, Curtis L. Wagner Jr., who is expected to hear testimony in the case all week at the Federal Energy Regulatory Commission here, said that if the market consisted only of Southern California, then El Paso had a "rather high level" of concentration in that market.
My only regret was not bringing a real bicycle (they don't have calorie counters, and nature has already set a rather high level of difficulty for the area, but the scenery is better than a stepping machine) to explore the countryside around Three Choirs.
The sample is biased with regard to rather young inhabitants with a rather higher level of education and rather higher incomes.
For now, a rather high-level critique will suffice.
As this quote suggests there are many opportunities and challenges in the steadily increasing amount of scientific data and there are a wide variety of rather high level reports, press releases, or statements given to support this claim.
Note that all existing proofs of Theorems 1 and 2 involve rather high level geometrical or analytical methods.
