The unclued lights are of a kind, verifiable in Brewer. Elsewhere, ignore two accents.
 

Across

 
1    Transfers year-groups (7)
11    Mushroom in cooker and much of the basmati (6)
12    Neighbours character’s hangers-on (7)
14    No Parking in island for Persian king (5)
15    Gamble on a lake drying after rain (5)
17    Powder that’s almost strong (6)
19    Catechism redesigned according to plan (9)
24    Plastic bags from carriages, having nothing new put back in (9, hyphened)
26    Enters hurriedly and attacks damagingly (9, two words)
29    Former hanger-on heard on Wipe Out (7)
30    Tall candlestick around one floor...