Basic site checklist
Sight lines, rights of way, restrictive covenants and the need for new entrances are buyer beware territory.
To get planning permission, i.e. approval from the authorities to build a new house, you must have adequate road entrance sight lines. A rule of thumb is that the higher the speed limit on the road, the further away you will need to be able to see traffic coming from both sides (sight lines), which may make a site impossible to build on if it is on a winding road with a high speed limit. Check the planning regulations in your area.
Your solicitor should also check for rights of way issues and any restrictive covenants that might limit what you can build. This is basic due diligence, but it can be surprising what is overlooked in the rush to secure the plot. You need to ensure that you can provide these within the land you own otherwise you risk creating a ransom strip whereby you need to pay over the odds for a small parcel of land from a neighbour to comply.
Be mindful that if you are applying for a mortgage, banks will require legal satisfaction that you have the right to access the road. A completely new entrance will in many cases require an application with the local authority with the stipulation that you undertake the works with an approved contractor.