If you are employed, regardless of how long you've been in the UK, you will automatically be covered under the NHS because you will be paying taxes. Otherwise, you have to be a resident, which means in order to be eligible for NHS coverage you will have had to live in the
UK for at least 12 months.
The UK Department of Health has a leaflet that outlines all of the situations that enable non-British citizens to have free NHS coverage:
• Anyone who is working in the UK for an employer who is based in the UK or is registered in the UK as a branch of an overseas employer (this includes self employed people). You must be actually working, not just looking for work.
• Any unpaid worker with a voluntary organisation offering services similar to those of a Health Authority or Local Authority social services department.
• Any full time student on a course of at least 6 months duration, or if less than 6 months is substantially funded by the UK government.
• Anyone who has come to live permanently in the UK. If you make an application for permanent residence after you get here you are chargeable until your application is approved.
• Anyone who has been lawfully living in the UK for twelve months immediately prior to treatment.
• Refugees and asylum seekers whose application is still being considered.
• Anyone employed on a ship or vessel registered in the UK or working offshore on the UK sector of the Continental Shelf.
• Anyone who receives a UK war disablement pension or war widows pension.
• Diplomatic staff working in embassies or Commonwealth High Commissions in the UK.
• Members of Her Majesty’s UK armed forces.
• UK Civil Servants working abroad who were recruited in the UK and employed by Her Majesty’s Government.
• Anyone recruited in the UK who works abroad for the British Council or the Commonwealth War Graves Commission.
• Anyone who is working abroad in a job financed in part by the UK Government in agreement with the Government or a public body of some other country or territory.
• Anyone working abroad for not more than 5 years as long as they have lived legally in the UK for ten continuous years at some point (including self employed people).
• Anyone working in an EEA country member state and contributing compulsory (not voluntary) UK national insurance contributions (class I or II).
• Anyone who is a national of an EEA member state, a refugee or stateless person or their dependant or survivor living in an EEA member state who is referred to the UK for specified treatment with an EC form E112 or E123.
• Anyone who is referred by their home country authorities for specified treatment in the UK under the terms of a bilateral agreement.
• Anyone who is detained in prison or by the Immigration Authorities in the UK.
• Serving NATO personnel, posted in the UK, who are not using their own or UK armed forces hospitals.
• UK state pensioners who have lived lawfully in the UK for 10 continuous years at some point, who now live for not more than 6 months each year in another EEA member state and not less than 6 months each year in the UK.
I would get travel
health insurance that is valid until you have a job, or until your permanent resident application has been approved, depending on what your long-term plans are.