The hit Channel 4 architectural show Grand Designs sees ambitious individuals build their dream family home, and this week's episode is no different.

In the first week of the new series, Manchester couple Colin and Adele learned the hard truths and the dos and don'ts of building their curved glass mansion.

The second episode in the series saw Tunbridge Wells-based Kate and Rob replace their rundown post-war prefab home that stood the ages and lasted a lot longer than expected.

After that, Canterbury-based couple Dorran and Vereuschka build an underground hidden home but trouble arose for the pair after they parted ways with their contractor and took on the project themselves.

They were then followed by Hertfordshire couple Matthew and Davidzo who built an Australian and Zimbabwean-inspired home on the sloping hills of the Chess Valley.

Derbyshire couple Mike and Sarah sought to create a medieval longhouse-inspired build in the week after with hopes to bring the family together.

Bedfordshire couple, John and Helen were next as they built a modernist pavilion with a £1.3 million budget to create a comfortable and accessible life for the pair. 

They were followed by London-based Corinne who attempted to create an impressive yet awkward extension as she looked for a fresh start following a few difficult years. 

The return of the much-anticipated re-visit of the North Devon couple who hope to build an impressive lighthouse-inspired home came right after that.

Fianlly, last week saw Kevin revisit a Somerset couple Vicky and Ed after they built their home on their own from a derelict cowshed. 

Now this week sees the re-visit of the Bolton couple as they build a fortress-like home on the southern edge of the West Pennine Moors.

Grand Designs revisits Bolton couple to build a fortress-like home

In 2015, traditional builder Paul and his wife Carol wanted to create their own fortress-like home on the edge of the West Pennine Moors of Bolton.

The build was set to be Paul's most impressive project, as he created an ambitious, eco-friendly, energy-saving build that would see him move away from his beloved traditional masonry for timber.

However, the couple's nerves grew as they dealt with obstacles from the harsh weather and a rapidly disappearing budget.

As their 15-month schedule came to a close, the home was still not yet built and left unfinished. 

Now six years later, Kevin returns to see how the build is coming along and if it was all worth it. 

You can watch Grand Designs at 9pm tonight on Channel 4 and All 4.