Across:
8 Evangelist doesn’t get visa (‘Evangelist’ doesn’t get ‘visa’ = engelt = GENTLE) by tender (GENTLE),
9 College (-C-) in Orient (Orient) sabotaged (= anagram indicator) (Orient = INTER-O-) by mass (-M) (INTERCOM) communications system (INTERCOM),
10 Group (group/lump = LUMP) losing leader (s) with depression (slump) (‘slump’ without ‘s’ = LUMP),
11 Couple ain’t (couple ain’t = PECULATION) prepared for embezzlement (PECULATION),
12 Miss (miss) out (= anagram indicator) (miss = M-SSI-) over a (-A-) frequency (-F) (MASSIF) or range (MASSIF),
14 Lands on island (CASTAWAY) with players (CAST-) – it’s not a home game (it’s an -AWAY game) (CASTAWAY),
15 Totally harmless (AS GENTLE AS A LAMB) in South Africa (SA) knocking back (= reverse indicator) (SA = AS) 1 across (‘gentle’ = GENTLE) with starters, appetisers, soups and (starters ‘Appetisers, Soups And’ = AS A) 24 across (‘lamb’ = LAMB) (AS GENTLE AS A LAMB),
18 Drunks (drunks/sots = SO-TS) consuming port (-P-) with his (-HIS-) (SOPHISTS) specious old teachers (SOPHISTS),
20 Easy going with no ego (‘easy going’ with no ‘ego’ = asying = SAYING), in a manner of speaking (SAYING),
22 Foreign politician (-MP-) consumed by new (= anagram indicator) election (election = INCO-LETE) (INCOMPLETE) is unaccomplished (INCOMPLETE),
24 Frenchman (Monsieur = -M-) in scientist’s place of work (lab = LA-B) (LAMB) is one of Mary’s followers (one of Mary’s followers / from ‘Mary Had A Little Lamb’ = LAMB),
25 Not the full piece (FRAGMENT) by German (German) boss (= anagram indicator) (German = -RAGMEN-) in paper (Financial Times = FT = F-T) (FRAGMENT),
26 Agent (Fed) comes back (= reverse indicator) (fed = DEF-) home (-IN-) to Spain (-E) (DEFINE) to explain (DEFINE).
Down:
1 That’s one in the eye (NEBULA in the cornea) for The Cloud (NEBULA),
2 Tread (tread/step = STEP) content of carpet slippers (content of ‘carPET Slippers’ = pets) going all the way back (= reverse indicator) (pets = STEP),
3 Maintains health (KEEPS FIT) of The Castle’s (the castles = KEEPS) leaders frozen in time (leaders ‘frozen in time’ = FIT) (KEEPS FIT),
4 Locked up in Alcatraz in California (locked up in ‘alcatraZ IN California’ = ZINC) for galvanising steel (ZINC),
5 Stone walls (stonewalls/delays = STALLS) in a stable environment (STALLS in a stable for animals),
6 Do Will’s job (do William Shakespeare’s job = WRITE A PLAY) or find work in the abbey (find work in The Abbey Theatre = WRITE A PLAY),
7 Mafia leader (Don = DO N-) is out initially (‘Out’ initially = -O) to cause suffering (HARM) (DO NO HARM) in a sworn statement produced by theatrical types (part of Hippocratic Oath is “first, DO NO HARM / primum non nocere”),
13 Don’t be fooled (SEE THROUGH it) this is all one can do for the Invisible Man? (SEE THROUGH him)
14 Sophocles dismissed pool (‘Sophocles’ dismissed ‘pool’ = shces = CHESS) with the mating game? (CHESS),
16 School (S-) is a safe place in Ring perhaps (-CORNER- a safe place in boxing ring) from endless (end ‘less’ = -S) (SCORNERS) Internet trolls (SCORNERS),
17 Squanders money (S-PENDS) all across America (-US-) (SUSPENDS) and hangs some out to dry (SUSPENDS),
19 Small (S-) stimulant (-UPPER) (SUPPER) to swallow before bedtime (SUPPER),
21 Calling (NAMING) direction (North = N-) to leading actresses (leading ‘Actresses’ = -A-) from Dynasty (-MING Dynasty) (NAMING),
23 Has a meal (EATS) with banks of eagle scouts (banks of ‘EAgle scouTS’ = EATS),
24 Covered by Eduardo De Filippo (covered by ‘eduardo dE FILippo’ = efil), in retrospect (= reverse indicator) (efil = LIFE) in biography (biography = LIFE).