Solution to 5D has been deliberately left unsolved and is to be answered by a non-regular/novice commenter, with proper annotation. Those who have answered earlier in the week, please give others a chance.
Open for anyone to answer, if not solved by 1 PM
ACROSS
1 Feeling a bit satisfied after extremely short flight (6) STAIRS {AIR}{Sa...d}<=>{ShorT}
4 A short time to have lunch out (4,2) BEAT IT {B{EAT}IT}
8 Taking spoiled salami, one ultimately gets some discomfort (7) MALAISE {SALAMI}*{E}
9 Henry delivered hash or heroin in metal container? (4,3) IRON ORE {OR+hEROIN}*
11 Visiting hot adult site, Mark gets aroused (10) STIMULATED {ADULT+SITE+M}*
12 Small drink, say, for skipper (4) SAIL {S}{(~ale)AIL}
16 John sat playing on account of these sets of cards (8) CANASTAS {CAN}{SAT*}{AS}
18 Cryptic clue about primarily nice relative (5) UNCLE {U{Nice}CLE*}
20 Went in haste, covering head (4) PEED sPEED
21 Radiohead's first hit single's unusually creepy (10) SLITHERING {Ra...d+HIT+SINGLE}*
23 Order servant to check room (7) CHAMBER {CHA{MBE}R}
24 Right away, rations drinks (7) POTIONS POrTIONS
25 Portion of crab soup in ceramic cups (6) PINCER [T]
26 Catches fish with outdated lures? (6) ANGLES dANGLES
DOWN
1 Taking public transport around is clever (5) SMART<=
2 Feared gangster's carrying a gun (7) ALARMED {AL}{ARMED}
3 New 'Listerine Strong' (9) RESILIENT*
5 In the East End, the masses misbehaved (5) E?R?D ()
6 No set exercises? (5,2) TONES UP {NO+SET}* [RA]
7 Result: After losing opener, entire team's out! (9) TERMINATE {eNTIRE+TEAM}*
10 Vessel with crew on board starts to head into port (9) STEAMSHIP {S{TEAM}S}{Head}{Into}{Port}
13 A UFO with small steps? Cool! (9) SPACESHIP {S}{PACES}{HIP}
15 Land in Amsterdam perhaps, says Spooner (5,4) TOUCH DOWN (~dutch town to touchdown)
17 A sign board above shows where to find a six-pack (7) ABDOMEN {A}{OMEN}<=>{BD}
19 Cheerful guy is always laughing basically (7) CORDIAL {CORD}{Is}{Al...s}{La...g}
21 Incident is investigated, as per report (5) SCENE (~seen)
22 Near-perfect ratings possibly worsening after partial review? (5) NINES [HIPS<=]
Reference List
Henry = H, Mark = M, Small = S, Australia = AU, Order = MBE, Servant = CHAR, Right = R, Date = D, Gangster = AL, Cool = HIP, Board = BD, Guy = CORD
