As promised a bit more -
From - Historical Records of the Buffs East Kent Regiment 1914 - 1919 by S H Moody page 141.
Order of battle that day for the 37th Brigade was 6th Battalion, Queen's Regiment on the right (South) supported by two companies of the Buffs, 6th Bn Royal West Kent Regiment on the left (North) supported by two companies of the Buffs, the 7th Bn, East Surrey Regiment in support.
It would appear reading further the Buffs B and D companies were to the right (South) and A and C companies were to the left (North).
After a few casualties, sustained by reason of the usual retaliation to our bombardment, the Queen’s and West Kents attacked. Very heavy machine-gun flanking fire met the Kentish men from the left (North) and the Queen’s from the right (South). “A” Company of the Buffs “ went over ” by plattons about 3.30 a.m., and the first wave suffered few casualties until the German wire was reached; but the succeeding waves of this company, and those of “C” Company also, suffered heavily in their advance. ........... The intense enemy machine-gun fire held up also the attack on the right (South) , and “B” and “D” Companies did not go into the struggle.
Total casualties on the 3rd. For the 6th. Battalion The Buffs, 11 officersand 263 other ranks.
There is a small map in The Somme. The day-by-day account. Chris McCarthy quoted by Herb Collector below which shows the 37th. Brigade West of Ovillers.
The Queens Own Royal West Kent Regiment 1914 to 1919 by C T Atkinson
See pages 184 to 189 here http://www.janetandrichardsgenealogy.co.uk/QORWK%20-%20C%20T%20ATKINSON%20Ch%2012.pdf
Which will give you more detail if William was in A or C companies. There are some sketches 18 & 19 after page 203.
The 6th Battalion, Queen's Regiment war Diary for the 3rd July.
See here - http://www.queensroyalsurreys.org.uk/war_diaries/local/1_6Bn_Queens/1_6Bn_Queens_1916/1_6Bn_Queens_1916_07.shtml
for the 6th Battalion, Queen's Regiment war Diary for the 3rd July.
It pins it down a bit better but as always it is not definitive enough.
I hope this is of help.