You might refer to the notes here
when you have read my answer.
The bare minimum that you need to achieve in order to avoid having to pay UK tax on your Saudi earnings is to spend at least one full tax year (6 April to 5 April) as a non-UK resident individual.
A new statutory residence test came into effect from 6 April 2013 which HMRC claims will make it easier to determine an individual's UK tax status. There is a series of tests which you need to apply to yourself. The second link I gave you is a brief synopsis of the rules which you can read in full in the first link. However, alot of that won't apply to you.
Unless you meet one of the automatic overseas tests, you will be treated as UK resident for tax purposes if you meet one of the automatic UK tests or one of the sufficient ties tests. See paragraphs 1.1 to 1.3 in the guidance note here
Based on what you have told me, if you will be working full time abroad you will be treated as non-UK resident for tax purposes if you work sufficient hours abroad and spend less than 91 days in the UK in a tax year and no more than 30 days working in the UK. See Definition A here
. The other two tests will probably not qualify you as non-UK resident as the number of days you can spend in the UK are very low. Quite simply, you need to spend less than 91 days in the UK in a tax year.
If you don't satisfy any of the automatic overseas tests, you will need to look at the automatic UK tests. Provided you don't fall foul of these tests, you will need to consider the sufficient ties tests and compare the number of days you have spent in the UK with the number of UK ties you have. If the number of ties you have is too many for the number of days you have spent in the UK, you will be treated as UK resident for tax purposes. See the ties table under "Leavers" here
. This can be avoided by spending less than 91 days in the UK in a tax year.
I hope this helps but let me know if you have any further questions.