Fairly straightforward, solving time 17 mins.
* = anagram < = reversed
ACROSS
1 T (RUM PETER) S st<
9 PRO (S) PER
10 CO (M PAN) y nap<
11 KAPPA hidden
12 SOLITAIRE Double definition
13 SENE CA (seen)*
14 MASS AGE R Mass is another Indy setter
17 OUT BREAK
18 W ALLOW
21 ELECTORAL e (energy) in (real clot)*
23 POS (I) T
24 E (PIG) RAM Mare< Saw = a saying
25 T (OR) PEDO OR = Other Ranks (depot)*
26/8/19 ELEMENTARY MY DEAR WATSON (Eternal words any may meet)* From Sherlock Holmes
DOWN
1 TAP DANCER (a CD parent)*
2 UNREST (tuners)*
3 P E CU LIAR
4 TEMP T (top of table)
5 READING G LASSES
6 SPOKE S
7 TOPPING \ THE BILL
15 ST A G P ARTY
16 DAIRYMAN (I am randy)*
17 O (PEN) ED
20 ELY TRA (rat)*
22 TH(is) RUM