Yes this site does the calculation
http://www.gb3pi.org.uk/great.htmlLatitudes and Longitudes are on the UNESCO site
Henderson Island to Rapa Nui is 1914 kms (1189 miles) so - under your 2000kms Els!!
Rapa Nui to Valpariaiso is 3678kms (2284 miles)
Gough to Robben Island is 2600 kms (1614 miles)