Decision time Barn vs Hunting for Land

Hi everyone, thanks for all of your continued support in my previous posts!

As mentioned, previously due to myself, being electric wheelchair bound and unable to walk, we decided to look for something other than a normal property due to my access needs.

I mentioned previously, there was a fully serviced barn in need of renovation. I was advised not to touch it as it was well overpriced. The owners have now come to our terms of the realising that they will not be able to get what they wanted for it.

During this time when our offer rejected we decided to look for and start hunting for land instead. Now this barn coming back has thrown a spanner in the works and we are potentially thinking of going through with it.

Builders have said that the barn could be ready in 6 to 8 months.

I was just wondering couple of things about land that would really help cement my decision.

Is there any sort of realistic time or average time, how long it takes people to find land?

If land is purchased with planning permission does anyone realistically know how long it would take to build a house if it is all approved?

Does anyone know the timeframe of trying to apply for planning permission on a piece of land that does not have it?

Many thanks George