FROM THE UK
There are schedule direct British Airways (www.ba.com) and Bulgaria Air (www.air.bg) from Gatwick to Varna. Wizz Air (www.wizzair.com) from Luton to Varna. Prices start at £34 one way (inc taxes) all year round.

Regional flights are also available from May to September, including www.balkanholidays.co.uk

There is a wider range of flights from the UK to Bourges Airport. The transfer time will take approximately 2 hours and 15 minutes. I have driven this myself and it's a very easy and pleasant journey. It will give you the opportunity to visit the resort of Nessebar which is beautiful.

There are various car hire companies which operate from Varna airport and locally in Balchik (www.compare.carrentals.co.uk)

Google Maps does not show Sunny Dream Complex, however i have noted where the complex sits on the map.