What a delightful morning's work-out. Cryptic clues with definitions that are cryptic in their own right. Nearly an hour with much time spent trying to unravel the wordplay as I know I have to explain the clues fully for this blog.
ACROSS
1 SWEEPS Ins of WEEP (blubber) in SS (ship)
5 SIDE ARMS Ins of ARM (member) in SIDES or ARM splitting SIDES (having apparent fit of giggles)
9 AIREDALE Cha of AI (A one, excellent) RED (ginger) ALE (beer)
10 UPTURN UP (with an advantage) TURN (go)
11 METATARSAL Ins of TATARS (fearsome invaders once) in MEAL (food) of that part of the foot, or its bones, between the tarsus and the toes
13 OTTO The Castle of OTRANTO by Horatio Walpole, (1717–1797) minus RAN (legged it). Thanks mctext@1 for the wordplay. A house name of many HRE from the 10th Century.
14 HAND H (hour) + AND (with)
15 PRIEST-HOLE *(HERE IS PLOT) a secret room providing a hiding-place for a Roman Catholic priest in time of persecution or repression.
18 ELECTORATE E (last letter of Burke or Hare) LECTOR (academic) ATE (worried) for the body that chooses. The allusion to the two names got me googling to get Burke and Hare who committed serial murders in Edinburgh, Scotland in 1827 and 1828
20 ha deliberately omitted. I hope you don't mind
21 CAIN CAIRN (a variety of Scottish terrier, dog) minus R (runs in cricket scoring)
23 CHICKENPOX CHICKEN (yellow) PO (river) X (cross) with a most misleading and original def, youngsters spotted with it. My COD for making me laugh
25 MEDICI MED (Mediterranean Sea) ICI (here in French, as indicated by in Marseilles)
26 STALKING S (son) TALKING (giving interview)
28 STRANGLE Ins of L (line) in STRANGE (novel)
29 PARADE PAR (norm) + alternate letters in AnDrEw
DOWN
2 WHITEHALL WHITE (in continental Europe, anti-revolutionary, therefore conservative) + H (hard) ALL (each person) for the London street with government offices; the British government or its policy.
3 EMERALD Ins of ME (writer of this clue) in ERA (time) + L (left) D (symbol for the old penny before 1971 when the pee came in when Sterling went decimal) Beryls are precious stones occurring in hexagonal crystals, of which emerald and aquamarine are varieties
4 SPA S (first letter of sick) PA (father, old man) for a health resort with springs
5 STEPS Rev of S (small) PETS (animals we love)
6 DOUBLESPEAK Quite self-explanatory if you write it doubles the peak
7 ANTIOCH AN + TI (rev of IT, sex appeal) O (old) CH (Companion of Honour)
8 MERIT Rev of TIRE (tax) M (millions)
12 APPROACHING A P (piano) PRO (player) ACHING (with strong desire)
16 IDA IDEA (thought) minus E (energy) for Princess Ida, or, Castle Adamant, a comic opera with music by Arthur Sullivan and libretto by W. S. Gilbert.
17 LAND OF NOD *(OLD FAN) + NOD (lapse in concentration) Reference to Genesis 4:16 And Cain (answer to 21Across) went out from the presence of the Lord, and dwelt in the land of Nod, on the east of Eden.
19 CANTINA CANT (insincere talk) IN (at home) A (answer) with concern (a business, in this case, a business house) for drinkers as def
20 MONIKER Rev of ins of E (English) + KIN (family) in ROM (gypsy) alias, nickname or real name aka handle
22 AGENT AGE (get on) + NT (New Testament, books) with vehicle as def
24 ISSUE IS (lives) SUE (girl or in Johnny Cash's case, a boy :-)
27 ASP WASP (White Anglo-Saxon Protestant, supposedly representing the most privileged class in US society) minus W (wife)
++++++++++++++Key to abbreviations
dd = double definition
dud = duplicate definition
tichy = tongue-in-cheek type
cd = cryptic definition
rev = reversed or reversal
ins = insertion
cha = charade
ha = hidden answer
*(FODDER) = anagram
yfyap88 at gmail.com = in case anyone wants to contact me in private about some typo