You should 'Talk to your local jobcentre' if you will be abroad for less than 4 weeks, you must 'Tell your local jobcentre' if you will be abroad for more than 4 weeks.
https://www.gov.uk/claim-benefits-ab...njury-benefits

Whilst there is no set limit on how many different 4 weeks holidays you can have in a year a different rule comes in. - The rule/law that says that you have to be 'habitually resident' in the UK to claim an Income Related benefit.
If you spend more time abroad than you do in the UK then you are not resident in the UK.