Just had a listen to RAF VOLMET on 11253 Khz USB, via a Wide Band WebSDR based in the Netherlands. It would seem the Station/Airfield ID's, announced via the Female Synthetic Voice, are the main problem (not all are readily intelligible) ... actual MET Data is otherwise good.
For those interested, here is the WebSDR URL.
WebSDR QTH Netherlands
Just punch in the desired frequency where indicated ...