Solution to 10A 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 Local going after vehicle on highway from London to Leeds? It can lead to reduction in gas (11) CARMINATIVE {NATIVE}<=>{CAR}{M1}
9 Wife leaves lawyer's coat (5) LAYER LAwYER
10 Grand proposal to install gas lines to every house is fanciful thinking (4,5) P?P? D?E?M (Addendum - PIPE DREAM [C&DD] - See comments)
11 American consuming sodium first? Disgusting! (10) NAUSEATING {US}{EATING}<=>{NA}
12 Money held by masseur obtained (4) EURO [T]
15 Warped space on 1st for wool gatherer (8) ESCAPIST {SPACE}*{1ST}
17 Following friend, on this day, turning into a follower of an Oriental faith (8) BUDDHIST {BUD}{THIS+D}*
19 Pertaining to quality of sound arising from ventilator after losing rivet (5) TONAL {veNtiLATOr}*
22 Gas used in Cochrane, Ontario (4) NEON [T]
23 A kind of presentation for electrical socket (5,5) POWER POINT [DD]
26 So, large things are thrown with this (9) SLINGSHOT {SO+L+THINGS}* Semi&lit
27 Son has fun returning female's ground tobacco (5) SNUFF {S}{FUN<=}{F}
28 Point carton out to get device (11) CONTRAPTION*
DOWN
3 Start to produce units manufactured to make feedstocks (6) INPUTS {Pr...e+UNITS}*
4 Adds, "Badly snapped" (7) APPENDS*
6 Entice ox running around university for performance (9) EXECUTION {ENTICE+OX}* over {U}
8 Meaning: One drink, after commencement of May (6) IMPORT {1}{PORT}<=>{May}
14 Cod dives strangely consuming current media storage device (5,4) VIDEO DISC {COD+DIVES}* over {I}
16 A new advice: With Italian wine, for starters (9) ANTIPASTI {A}{N}{TIP}{ASTI}
17 In absence of war, brainwash distraught and exile (6) BANISH {BraINwASH}*
18 After school, parent gets choke (7) SMOTHER {S}{MOTHER}
20 The French aristocrat is pardoned (3,3) LET OFF {LE}{TOFF}
21 Rose, you and I punt badly (4,2) WENT UP {WE}{PUNT}*
24 Put in vase and badly ruin before noon (5) INURN {RUIN}*{N}
25 Against rebellious Anglican leaving clan (4) AGIN ANGlIcan*
Reference List
Wife = W, Day = D, Large = L, Son = S, Female = F, Yankee = Y, University = U, Fine = F, Current = I, New = N, School = S, The in French = LE, Noon = N