What does the cryptic crossword clue "Rash lot fretting about prolonged struggle (5,2,8)" mean?

The wordplay uses an anagram. anagram of RASH + LOT + FRETTING = TRIALOFSTRENGTH The answer is TRIALOFSTRENGTH.

Rash lot fretting about prolonged struggle (5,2,8)

Daily Mail Cryptic #17075 | 1 Down | 2023-04-13 flower