They're blown away by bubbly person Helen used regularly (10)
I believe the answer is:
alpenhorns
'they're blown' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.
'away by bubbly person helen used regularly' is the wordplay.
'away' becomes 'a' (abbreviation as used in sports fixtures).
'by' means one lot of letters go next to another.
'bubbly' indicates an anagram (I've seen this in other clues).
'used regularly' means one should take alternating letters.
The alternating letters of 'helen' are 'hln'.
'person'+'hln'='personhln'
'personhln' anagrammed gives 'lpenhorns'.
'a'+'lpenhorns'='ALPENHORNS'
Can you help me to learn more?
(Another definition for alpenhorns that I've seen is " wind instruments".)