Buying a house from the GF parents , does it require a hip ? What do i need to consider in regards to conveyancing?

If it hasn't been advertised then no – you don't. Conveyancing could just be done between 2 solicitors. Make sure your solicitors know you don't need one if it hasn't been advertised – mine didn't – until I showed their 'expert' the legal detail.

You will still need an EPC prior to Exchange of Contracts (the energy efficiency bit) – should be able to get one for £50-80ish

Edit – it's sellers responsibility to supply this, strictly.

You dont need anything other than a solicitor to sort the land registry etc, and you dont need two solicitors, one acting on behalf of both partys will be fine, cheaper and a lot quicker. Just done something very similar with no problems.

What Grimy said – we also sold privately to mates.