AIBU to ask how you go about selling a plot of land with planning permission to build?

[PlanningPermission]

I am looking to sell current home and downsize to somewhere in a nearby town. I am getting on a bit now, so think it would be better to move somewhere less remote.
Our property has a large garden. The previous owner bought two adjacent plots and built our existing house on just one of them. The second plot forms part of of our garden.
There was originally planning permission to build a house on the second plot. This expired years ago.
I was wondering about applying for planning permission to build a house on the second plot, which is currently just garden. Thought that I could then sell the plot of land with planning permission already granted.
Is it a case of engaging the services of an architect to get the ball rolling? Or alternatively, do I need to firstly speak to the council to gauge if planning permission would be likely to be granted?
Any advice would be welcome x

Speak to the council and see what they say. It might be easier and better to go for outline pp. Also don’t overestimate the appeal of a second site on your land. Many buyers ont be interested,

Be a bit careful - 2 small plots with cramped,overlooked gardens can be worth less combined than a single large home with a much bigger garden & potential to extend.

Is there convenient road access to the second plot?

An overage agreement might be easier.

Ask an estate agent

I would speak to the planning office first, but usually it would just be a case of resubmitting the planning.

Most councils offer a pre-planning service, which you may need to pay for, where you can gauge if an application might be likely to be passed. I presume there's access from the highway to the second plot already, separate to the access to the main plot?

I'd speak with a couple of agents to get an idea of how much it would devalue your current property. You'd also need to factor in the cost of legal fees to divide the title (if it is currently all under one title deed).

Thanks so much everyone for your information and very useful ideas.
To answer the question about access, the second plot is on the side of our house. If there was a house on the second plot, an additional driveway from the new house down to the road would have to be created.
The existing entire plot is half an acre. If we sold the second plot, each house would have 1/4 acre each.

We have done this. Spoke to planning who were supportive of the idea, spoke to specialist estate agent for rough valuation, engaged planning consultant and architect, obtained planning, put on the market. Took several attempts to complete because of time waters and conveyancing was complex with splitting the title (in Scotland, which I think is slightly different re land registry).

To answer the question about access, the second plot is on the side of our house. If there was a house on the second plot, an additional driveway from the new house down to the road would have to be created.

That sounds as though you'd need to apply for planning permission for a new access onto the highway. The new title deed would need to include that legal right of way, so it's not straightforward.