Green’s Dictionary of Slang

dolly n.4

[ety. unknown; ? link to SE tallow, of which candles were made; or school sl. tolly, a candle]

(UK tramp) a candle.

[UK]Partridge DSUE (8th edn) 326/2: C.20.

In phrases

dolly up (v.)

(UK tramp) to heat water or tea with a candle.

[UK]Partridge DSUE (8th edn).