Wheatley gave their Oxfordshire rivals from Littlemore a helping hand on Saturday by beating Chesham 25-22.
However, the purple men were forced to come from behind after trailing 18-19 at half time.
A kick from Bouchier extended the lead to 18-22 before Wheatley pounced on a tired Chesham to eventually see out the match 25-22.
Despite a resolute performance from Wheatley, the lack of bonus point at the final whistle means Chesham are guaranteed third in the Berks Bucks & Oxon Premier, one place above Wheatley on 47 points, with one game to go.
The result also did rivals Littlemore a favour who secured second place with a 71-7 win over Bletchley.
Elsewhere, Didcot’s trip to Milton Keynes was one to forget as the fell 23-15 in Buckinghamshire.
At the other end of the rugby pyramid, second placed Chinnor lost their National League 2 South clash at Canterbury 52-29 while midtable Henley Haws were beaten 36-19 by London Irish Wild Geese.
In the South West 1 East, Grove fell 39-15 at Swindon as bottom club Bicester lost 57-20 away to Wimborne.
Banbury punished Witney 36-19 but had to settle for second after Old Patesians were crowned champions after beating Oxford Harlequins 34-7.