As you are registered as a Private seller and not a Business seller, the holiday mode is not available for you.
There is a Time Away feature, see here:
https://www.ebay.co.uk/help/selling/selling-tools/time-away?id=5137&st=3&pos=1&query=Time%20Away&int.....
Or, you can just end all your items, they go into your unsold listing for 60 days if you are on My eBay selling or for 90 days if you are on the Seller Hub. You can then relist them any time from there, during those periods.
@flami_79
