I'm struggling on the censuses at the moment (I'll keep going!). Found a possibility for Andrew's parents.
From IGI we have the following children showing for Andrew and Margaret Hair following their marriage in 1846:
1. JANE FRASER JOHNSTONE Christening: 30 JUN 1849 Dumfries, Dumfries, Scotland
2. HELEN JOHNSTONE Christening: 18 MAY 1847 Dumfries, Dumfries, Scotland
3. MARTHA TRAINER JOHNSTONE Christening: 30 OCT 1851 Dumfries, Dumfries, Scotland
4. MARGARET HAIR JOHNSTON Birth: 10 JAN 1856 Dumfries, Dumfries, Scotland
It would look like Arthur b.1854 in England was probably their first born son and as such Arthur could well be the name of Andrew's father.
There is a submitted entry on IGI for the birth of an Andrew:
Andrew Johnstone Christening: 08 NOV 1825 Dumfries, Dumfries, Scotland
Parents: Arthur Johnstone and Jane Fraser
Mother's name above could link up with child NO.1
There is also an actual extract on IGI for this marriage below, which could mean that Arthur Snr. may have remarried. Name of second wife could also connect with child No.3 above:
ARTHUR JOHNSTONE Marriages: MARTHA TRAINER
Marriage: 06 JUN 1834 Dumfries, Dumfries, Scotland
There is an 1851 Census entry for Arthur and Martha, and Arthur's occupation also connects with Andrew's:
Arthur Johnstone 52, Master Shoemaker Employs 1 Man, b. Dumfries
Martha Johnston 38
Elizabeth Johnston 13
Arthur Johnston 11
Charles Johnston 8
John Johnston 6
Cath Mary Johnston 2
Address: Kirkgate, Dumfries
I'll try and find Andrew's entry in 1841.
Monica