I recall a condensate tank and automatic pump that can be fitted alongside a condensing boiler, which allows condensate to be tranferred to a remote or higher level drain.
Here's a few. Mount at the normal drain level from the a/c uynit and the pump should lift condensate out as you need.
http://www.saniflo.co.uk/products/index/show-product/lang/en/type/all/id/30
http://www.saniflo.co.uk/products/index/show-product/lang/en/type/all/id/31
http://www.saniflo.co.uk/products/index/show-product/lang/en/type/all/id/39
http://www.plumbcenter.co.uk/product/pump-house-boiler-condensate-pump-2ltr/
You'll need to do a bit of thinking though, January 2016