Planning advice can be obtained either directly from your local planning authority, or an experienced town planning consultant. Your LPA will always provide useful planning advice notes on their website which you can use to do your research. Based on that, you can submit a request for pre-application advice to your local planning authority. However, it may take several weeks to receive a response.
If you choose to seek advice from a town planning consultant, you will be able to communicate with them straight away and receive all the planning advice you need to make your next move. Having a professional look at your plans early on can help you to save money and time as it will ensure you are following all the latest rules and regulations relevant to your circumstances, before applying.