The renovation project is complete. It has taken eight months. Now the process of selling it, and validating our efforts will begin. 
We had three estate agents visit and plumped for the one with the Mont Blanc pen. I will explain...
The first one was who we bought the property from. A pat on the back for our work was welcome, but as it was the only property they had sold in the area and they based their valuation on a nearby town, rather than the slightly rural area, it didn't appear that their experiences would match our hopes for a sale.
The second visitor had used a Rightmove application that allows Estate Agents to see what the market rate in an area should be. He valued it at exactly that market rate. As there appeared no consideration for the fact that everything from the kitchen to the heating to the wiring to the garden was completely brand new, we didn't really think he knew what he was on about. A quick search of other properties on their books suggested much the same.
The guy with the Mont Blanc pen had also sold two houses in our road this year and currently had the most expensive house in the road on his books so we chose him for the job.

I couldn't resist. I know I should avoid all temptation, but I just couldn't help it. It was only one mouse click away, what could I do?
I visited Rightmove. 
I know I shouldn't have, but within two hours of searching I had found fourteen properties to renovate and five potential building plots.

A second member of the team paid a visit. Good to know what they're trying to sell, apparently.
Great. Just a matter of time...

A third member of the team popped around. 
This is great - the whole office has seen our house, told us how wonderful it is and although a Christmas caveat was added, viewers would be along soon.

A second branch of our estate agent, this time from a local high street, sent a team member around today.
The more the merrier. Anyone that can sell our house is welcome any time.

I haven't accidentally pressed the input key too many time.
Another team member from the secondary estate agent office came to have a look around. 
That's my lot - I think everyone from my estate agent that is likely to sell the house has now seen it.

I have added the link below because this is where I placed our findings. It appears that we will have to move into the property or pay a rather large penalty.

Have I got this wrong? 
I have read through some basic information and it seems that you don’t have to pay anything for Developer’s Finance. You just have to pay back interested accumulated on your lending over the period of the build. 
Looked at holidays to Brazil.

Made a call to Buildstore to learn what we could about Self-Build mortgages. 
The helpful man on the other end explained the basics, and after I said that the plan was to build a property and sell it, I was advised that a ‘Developer’s Mortgage’ would probably be the most suitable product. I asked for a case study so that I could fully understand the financial implications.

Although I had chased them, Buildstore had been waiting to hear back from a lender with a reply to my case study question. My impatience quelled, I finally heard back from them today. 
Good grief, early elation at the prospect of free money, turned into despair, as it was revealed that borrowing £200,000 for just 10 months would cost about £35,000 in interest. 
I quickly wrote back and asked for information on Accelerator Mortgages. 
Postponed the idea of a holiday to Brazil.