WW1 Advice please?

[ALAMO2008]

13889 Thomas Bestwick enlisted into 16th King's Liverpool Regt on 29/08/1914 in Liverpool from his home in Wolverhampton he Attestation papers imply he went to France from Folkestone on 04/07/1916 and was transferred to the 20th Pals on 15/07/1916 and Killed in action near Thiepval on 30/07/1916  as a Sgt.

No mention on his record of promotions, could this be perhaps of previous Military Service ?
He is missing from 1901 & 1911 Census
I did find a Pte 7322 Thomas Bestwick in the 2nd Btn North Staffs entitled in 1901 to the South African Medal which could be him.

Why has his Record been Stamped as though he was entitled to 1914/15 Star when Medal Card and record at Home suggests not entitled to it.
Is Stamp just a mistake?

[jim1]

Promoted to Sgt. 7/11/15.

[ALAMO2008]

Cheers Jim1
His youngest Brother Albert Henry  seems to have challenged the War Office over the Medals
which they sent to the Eldest Brother John Henry

[jim1]

Tears before bedtime that's for sure.
Link to map.
The 20th. were at Maltz Horn farm A.6.a.
They set off for Maltz Horn trench red circled in blue.
They then headed north to Maltz Horn Ridge.
All of this while shrouded in fog.
The assault became disjointed with men getting lost.
However they did achieve their objectives with 169 casualties
+ 119 missing.
http://www.rootschat.com/links/01qbp/