AIDOAIR
The Ryanair 737-800's are not "de-rated" engines, yes for take-offs performance permitting the engines will be de-rated to save engine wear/maintenance etc but I stress the point performance permitting. The aircraft themselves have 26k/24k/22k and can be further de-rated by assumed temperature. The only slight difference FR's aircraft have is they don't have the "Bump" which would allow 27k. Even at 26K full thrust the performance would not allow take-off from BHD to continental Europe with the necessary fuel OR worthwhile passenger load and this would only be compounded when the runway is wet.
Regards