ACROSS
1. <stuffy> FROWSTY = F ROW STY
5. <they're pushed> BARROWS = BAR ROWS
9. <friendly> ON SPEAKING TERMS = (PRANKS SEEMING TO)*
10. "DOE" = DOUGH <green>
11. (PLUG IN THE)* = LIGHTEN UP <relax>
12. WEE KNIGHTS = WEEKNIGHTS <certain periods>
14. ←_ELS_ _I_← = ISLE <Anglesey?>
16. <charge> RATE = RAT + _E
18. GUARD* AT IO + _N_ = GRADUATION <ceremony>
21. <inflate price of> OVERVALUE = (LOUVRE VA)* + E_
23. <luggage> CASES <suits>
25. GOOD + TIME + CHARLIE = GOOD-TIME CHARLIE <partier>
26. <fast> RAPIDLY = D inside APRIL* Y
27. <Mass> LITURGY = IT inside LURGY

DOWN
1. R_ inside FOND = FROND <part of palm>
2. <mysterious> OBSCURE = O BSC U _R _E
3. SEE THING = SEETHING <boiling over>
4. <provinicial> YOKEL = YOKE L_
5. (GET BEHIND)* = BENIGHTED <ignorant>
6. <spin> ROTATE = _R _O _T _A _T _E
7. <he represents the sky> OURANOS = ←SONAR← after OU
8. <endlessly frustrating> SISYPHEAN = (PAY SHE)* inside SIN
12. <hawk> WARMONGER = (GONE* after WARM) R
13. <lord> GORBLIMEY = G ORB + LIMEY
15. <analysis> BAR CHART = ←CRAB← + HART
17. POOTLE* outside O = TOE LOOP <skating manoeuvre>
19. <narrowminded> INSULAR = INSUL[-t] _AR_
20. IV YT _O + D = IVY-TOD <bush>
22. EEL outside X C = EXCEL <are amazing>
24. "CD" = SEEDY <in bad condition>