Am planning to commence a DONE4 from CAI but am still mulling over the options for a side ticket to get there before and back after.

BA discounted Y return is ~ GBP 500, there are cheaper alternatives using non-OW carriers such as Austrian Airlines, Olympic, Air France, Egyptair and Alitalia [though the layover times for Alitalia are extreme].

If I buy a 1-way Y ticket with any of these, I could get away with around GBP 200. I could then combine this with a 1-way C fare on BA CAI-LHR of GBP 500.

Anyone lurking here have any suggestions for choosing a non-UK point of origin to get a good Y/C deal and keep all travel within OW?