The food at the medieval is a veg soup, full roasted chicken and jacket spud and ice cream. Whenever I have been I have always enjoyed the chicken (soup, maybe not!!)
If you knw the menu before you go I cant see what there is to complain about, chicken is chicken?
As for taking 2 taxis, I would not recommend as it will cost you a fortune!! The buses normally pick up in the costa adeje area at approx. 7pm and doors opan at 8pm, at the most I reckon the journey will be about 40 mins. And the saving on taxis will be worth it!!