The Prince and the Showgirl - solution

Below the break is the solution and notes for The Prince and the Showgirl.

Answers to clues without definitions were SIZZLES, MARV, SOREN LORENSEN and LOTTA, friends of CHARLIE AND LOLA in the children's book series by Lauren Child and subsequent BBC adaptation.

Clues

Across

1 Wits end for Farage: pair of animals ruined statism EPIGRAMMATISTS
E + PIG + RAM + STATISM (anagram)

9 Having had a few drinks, could be generous towards the waiting staff? TIPSY
facetious definition based on ballsy, gutsy, etc

10 One who looks about 15, say, turning more like a typical teenager? STROPPIER
'SPIER' around PORT backwards (ref to 15ac)

11 After year in empty abattoirs, recruit Scottish beef producer AYRSHIRE
YR IN A(battoir)S + HIRE

12 Standard family sweet treat PARKIN
PAR + KIN

14 Unknown number left among masses SIZZLES
 Z + L IN SIZES [wordplay only]

16 I'm not up for that party without any beer? NO CAN DO
 facetious definition of a 'no-can do'

18 Tide's turned in rubber EBB
hidden backwards

19 Comparatively thick criminals THIEVES
 "thick as..."

20 Each clue for Sherlock Holmes is nagging annoyance EARACHE
EA + RACHE (clue in 'A Study in Scarlet' or the BBC Sherlock equivalent)

21 Draw a line under vacuous French article describing it ALLURE
A + L + LE around U(nde)R

23 Fellow with returning urge for underhand practices COVER-UPS
COVE + SPUR (rev)

26 Retaliation in kind of trait involved in race TIT FOR TAT
OF TRAIT (anagram) in TT

27 Works for electronics manufacturer CANON
two defs

28 See preamble CHARLIE AND LOLA

Down

2 Dad cooks a pizza with a bit of red snappers PAPARAZZI
 PA + A PIZZA R(ed) (anagram)

3 Symbol in ugly phrasebook GLYPH
hidden

4 Extremely opaque substrates stirred ABSTRUSEST
SUBSTRATES anagram

5 Half of members leaving Maroon 5 MARV
MAR(oon) + V [wordplay only]

6 One requires a hard floor and carpet renovation TAP DANCER
AND CARPET anagram

7 Abuse staff STICK
two defs

8 Tender stories: Home Counties news following them all SOREN LORENSEN
SORE, LORE, SE all followed by N(ew) [wordplay only]

9 Annalist worked with tract covering UK and US (13) TRANSATLANTIC
anagram of ANNALIST with TRACT

13 International organisation petition a number following Old Testament's description of Adam UNBEGOTTEN
UN + BEG + TEN after OT

15 Football team's food served with onion ring sent back LIVERPOOL
LIVER + LOOP (rev)

17 Sort seeing plenty of the moon's new month lunar cycle NOCTURNAL
N + OCT + LUNAR (anagram)

22 Briefly, many thanks LOTTA
LOT(s) + TA [wordplay only]

24 Office subdivision put in sterling work EXCEL
two definitions (Microsoft Office)

25 Swelling tickling your eyelid primarily STYE
initial letters

Notes

This puzzle was of course constructed as an excuse to use the excellent title. The theme ought to be Googleable after solving a couple of the wordplay-only clues, or guessed with enough letter in 28 at which point the remaining friends can be deduced (one does not realistically expect SOREN LORENSEN to be guessed ex nihilo.

One clue, 15, was reworked after the puzzle was posted. Originally the clue read "Food served with onion ring sent back here? (9)", with 'here' as the definition to indicate a place. Although there is some precedent for this, such as a Rufus clue for HARTLEPOOL with 'where' as the definition discussed by the Guardian crossword editor in 2009, I don't think this is really sufficient.

The setter has sadly neither read nor watched any of Charlie and Lola's exploits.