Hi,
In your Self Assessment Tax Return, the UK VAT is included in the declared gross profits. In SA103F the UK VAT is declared as an expenses, so that it can be deducted from the gross profit, along with the other expenses.
If you make General Rule Supplies overseas then these would be classed as Outside The Scope of UK VAT and would not go towards your turnover for VAT registration purposes and so you could ignore the £1000 supply as regards your turnover.
Please see the guidance below:
Place of supply of services (VAT Notice 741A)
Who should register for VAT (VAT Notice 700/1)
Thank you.