Bletchley held on to top spot in the Southern Counties North division with a single point victory over Stow-on-the-Wold.
The teams exchanged penalties, with Stow leading 6-3 before Bletchley exploited their possession from the set piece and when Steve Allen set Turnbull away, space was created down the right wing.
Turnbull produced a neat offload to Gibbings and the winger skipped down the touchline towards the try line.
There was still work to do, but the youngster neatly sidestepped the two covering defenders to score his second try in two games.
Harman produced a superb conversion kick from the side line to put Bletchley in front for the first time.
Another Stow penalty reduced the arrears to 10-9 at half time.
They re-took the lead four minutes in to the second half, before Bletchley crossed the line again.
A scrum to Bletchley after Stow knocked on at a ruck gave replacement scrum half Tom Foster the chance to break through before offloading to Matt Nobes running in support. Nobes ran in under the posts, Harman converted and Bletchley were back in front.
The game sparked in to life though, as poor play by the visitors after the restart put Stow back in front as a loose pass was well fielded by the home side. Desperate tackling prevented the try initially, but quick thinking by the Stow scrum half when the referee awarded a penalty saw him tap and go and score the try that put Stow back in front. The easy conversion kick wernt over to give them a 19-17 lead.
But with seven minutes to go, Stow were penalised at the scrum and Harman kicked another over the bar to put Bletchley back in front, holding on 20-19 to secure top spot for another week.
Milton Keynes weren’t so lucky though and lost more ground in the title race, slipping up at home to Aylesbury.
The first 10 minutes were dominated by the visitors and a penalty put them 3-0 up. From the restart Aylesbury were able to snatch the ball and the flanker was over the try line for a easy score. With a missed conversion Aylesbury were 8-0 up.
The game remained evenly balanced for the next 20 minutes with Milton Keynes gradually making inroads into the Aylesbury defence. Wesley McGimpsey made a good break on behalf of City and was able to pass to Ashley Target who went over the Aylesbury try line.
Phil Powell was able to convert to make it 8-7.
Another penalty for Aylesbury though gave them a four point advantage at the break.
City started the second well and were pressurising the Aylesbury line. A handling error allowed Aylesbury to gain control of the ball and broke from their defence towards the City 22 line. A further penalty was awarded against Milton Keynes which Aylesbury took quickly and scored in the corner whilst City was still organising their defence.
The home team continued to pressurise the Aylesbury try line. A poor defensive kick from Aylesbury was well gathered by Gavin Whitehead who avoided two tackles and was able to pass the ball inside to Ashley Target who scored a good try. With 20 minutes to go the score was now 12-16 and City were now within points for a win.
With just 10 minutes to go Aylesbury were able to close the game down by scoring a further try. City’s hopes were further dashed by Jamie Treverton and Rob Matthews receiving yellow cards.
Next week, Bletchley host third place Thatcham while MK travel to Drifters.