Thanks for your very helpful suggestions and offers of assistance.

No joy at the electrical shops near the Otogar which are the largest in Fethiye. They don't seem to stock much Apple kit. But I found a 4 in 1 HDMI combo adaptor at the Dogus electrical shop on the opposite side of the road from the Mulberry Tree cafe on Carsi Caddesi, they were very helpful and spoke good English. Quite expensive at 100ytl.
Tested this afternoon and works fine, so we are now able to stream from IPAD using VPN.

The combo adaptor also has a USB to ipad adaptor and a connection for AV cables.
Dogus seemed to stock a wider range of cables and adapters than the other stores I visited - including Caspers and Gold, also on Carsi Caddesi, which is the top or back road of the one-way system in Fethiye.