Then came the much-anticipated re-partnering with Honda, which, over the course of three turbulent seasons, saw the multi-champions finish 10th, 7th and 10th (again), respectively, gaining a total of 133 points over the entire three years.
Eventually, the pair opted to go their separate ways, and while Honda hasn't taken the significant step forward many were expecting, its performance with Toro Rosso has been enough to convince Red Bull to end its own turbulent partnership with Renault.
Meanwhile, for the second time in its long history McLaren partnered with a French manufacturer, though again the results have hardly been inspiring. Despite a strong start to the season by the time of the summer break the Woking outfit - like its fellow multi-champion rivals at Grove - had become a sad footnote in the 2018 standings.
Though the Woking team finished sixth overall, its best result since 2014, let's not forget that Racing Point Force India finished just ten points behind, despite contesting just nine races, and that over the course of those nine races McLaren scored just ten points.
If nothing else however, 2018 put an end to McLaren's ludicrous claims during the Honda partnership that it had the best car and that the power unit was the root of all problems, for this season the MCL33 was a dog.
"On the one hand, it was frustrating," he tells BBC Sport. "On the other, we are committed to this.
"The way we were heading, the change was bound to come," he says of the split. "Tremendous respect for Honda but the relationship wasn't working and so we had a civilised discussion and we decided to part ways.
"We will see this through," he added. "Frustrating, because we are racers at heart, but you just have to power through."
With free engines and financial backing, the Honda divorce is said to have cost the Woking team in the region of $100m (£78.8m), a figure in which the few new sponsors the team has attracted has barely made a dent.
"We're confident we know why we haven't been able to develop this year's car," says Sheikh Mohammed. "There is a fundamental problem, and we think we've addressed it.
"I don't know if we want to disclose what we have discovered and why, but we have taken steps, and the development of next year's car has helped us understand what went wrong here."
Admitting that the issue was not discovered until "after the summer break", he says: "Had we discovered that in April we would have had a B car, but it was too late."
In an effort to get the team back on track, Sheikh Mohammed reveals that Mumtalakat, investment fund of the Bahraini government, is pumping more money into the team, which earlier this year saw Canadian businessman Michael Latifi invest £203.8m.
Though the fruits of this investment have yet to be seen on track, behind the scenes there are big changes, with James Key recruited from Toro Rosso - though currently consigned to his garden - and Pat Fry returning to his spiritual home after his time with Ferrari. Indeed, the 2019 car will be the work of Fry and Andrea Stella who headed to Woking at the end of 2014 from Maranello along with Fernando Alonso.
One way or another, 2019 is going to be a crunch year for the Woking team... in the meantime check out the live betting odds.
Check out our Tuesday test gallery from the Yas Marina, here.