An innovative couple whose Scottish home features on Channel 4's Grand Designs series are throwing their doors open to the public on Sunday.

Reuben Welch and April Marr will tell people about the trials and tribulations of their ongoing five-year project transforming a derelict school janitor's house in Edinburgh.

Visitors to Couperfield House in Leith will be able to see the dramatic interior of the couple's home, including a curved mezzanine with a standalone bath.

They can also meet the architect who helped the thirtysomething couple turn their ideas into reality.

The invitation is part of a nationwide Grand Designs open day revisiting some of the most popular properties from the series, with a special episode about the open day broadcast in the next few weeks.

Anyone wanting to have a look around the Leith property on Sunday should apply online for free tickets, which are being allocated on a first come, first served basis.

Kevin McCloud, presenter of Grand Designs, described the house as a testament to the couple's enthusiasm. He said: "This house is a shining tribute to Reuben and April's hard work and they've breathed new energy into it."

Mr Welch said yesterday he was looking forward to the open day.

He said: "It will be quite fun."

On Sunday their house will be open to visitors between 10am and 4pm. To book free tickets visit www.channel4.com/4homes.