well just got it back it turns out the rubber washer for the washer jet had been put on the wrong way around (not by me before i bought the car) they have been turn the right way also like you said rich with a bit of sealent,

the spark plug is still stuck so im going to squirt a bit of penetration fluid in the spark plug well once a week for a month then see if it will loosen, if not then try for 1 more month then after that a lot of force will be used with a long ratchet
if it loosens then but if it snaps then its a head of job at £700