Hardly anything on this route - last year there was quite a few dates, this year it's seriously limited (as OP mentioned, even using Companion voucher). That goes for BHD, MAN, JER, EDI etc too.

I thought the new voucher was great with additional availability, now everybody has it - seems not as useful.

In fairness I can't even check BA Avios availability lately as more than half of the time I get an error message.