Financial Times 13,486 / Styx

One of those strange puzzle that took longer than average to gain an initial toehold, but then offered decreasing levels of resistance thereafter as the answers seem to flow with continual acceleration.  A couple of vocabulary blind spots (10A, 7D) prevented me from attaining terminal velocity however.

As a programming note aside: I’ll shall be airborne for a decent slug of Thursday, so unable to respond too promptly to  corrections/questions. TTFN

Across
1 BOLDNESS – (L + end<) in boss.
5 TINSEL – tin + sel{l}.
10 DIES NON – One’s* in din.  Latin phrases are rarely bread-and-butter to me, so I had to wait for all the checkers before figuring out the wordplay plausibly.
11 OUTLAST – {y}out{h} + last.
12 ENEMA – enem{y} + a.  The second time in a couple of weeks  that this answer has cropped up during my blogging duties.
13 ITINERANT – tine in (I + rant).
14 DESERT ISLAND – a in (Endless dirt)*.
18 SCARLET FEVER – scar + (felt)*+ ever.
21 AUSTRALIA – (A ritual’s)* + a.
23 ERASE – r in ease; pretty much as instructed by the clue…
24 INSIGHT – I + (s{oldier} in night).
25 GROWLER – L in grower.
26 TIPPER – double def’n.
27 PRISONER – son in prier.

Down
1 BODIES – B.O. (bodily odour) + dies.
2 LIEGES – e.g. in lies.
3 NONPAREIL – No + (pare in nil).  Second only to nonsuch in the realms of “non…” words, if you ask me.  It’s case is not helped by applying its superlative nature to these far from “ideal” sweets.
4 SENTIMENTALITY – sent + I + mentality.  A bit watery for my taste.
6 ISTLE -Is + {f}elt<.
7 SOAKAWAY – (oak + a) in sway.  Another new word to me, and the last one in.  But I got lucky with a bit of divine inspiration after staring at the slightly daunting S_A_A_A_ for about twenty seconds.
8 LATITUDE – (a tit) in duel*.
9 DOG IN THE MANGER – Do + gin + them + anger.
15 SKELETONS – (keel not) in SS.  I liked this one due to the smooth surface.
16 ESSAYIST – (say is) in Est.
17 PASSES UP – asses in pup.
19 CALL ON – all in con.
22 ROGUE – (Irish) {b}rogue{s}.