Solid stone house, been re-pointed at some point with cement instead of lime, so I'm sure that isn't helping.

The pointing is fine, and the window itself seems ok.

The first window is single glazed, metal framed, with that crap sliding secondary glazing in front.

The second window is double glazed.

The wall gets incredibly wet when there is hard rain.

Will rendering around the window solve this?

The house is well ventilated with wondows being open most of the year. Also, the washing is done in an outside utility room and the bathroom and kitchen are at the opposite end of the house.

these can be a pain sometimes...
done loads like em though...
i reckon the best thing to do is the hosepipe test and by that i mean start immediately above or to the side of the window and direct the hose straight at the corners, then the brickwork and work your way upwards slowly until it becomes evident...
thats if its running in....

if its just getting very damp during a period of heavy rain its just penetrating damp and the treatment for that is repoint whatever isnt soundthen turn your attention inside allowing the outside to dry out on its own...

looking at the building, with it being what it is i'd be looking at having the reveals of internally and lining em with 25mm cellotex (or whatever you can get on there with plasterboard or even gripfill some 25mm insulated board on and skim em back up, i'd prolly have the window board off too...
its a solid stone property mate, the only way imo to be absolutely sure is to tank all the internal walls, leaving the outside alone to breathe...

looking at the cills (or lack of seeing as theyre on stone) i'd double check all the sealant, in fact the full perimeter while youre it (but youll have done that anyway)

i dont think rendering the wall round the window is going to solve the problem to be honest and if its got waterproofer in it, it will stop the wall drying out after its rained as the water will just penetrate above and soak through... though i agree it may tidy it up a bit, you could even try your hand at a bit of 'pargetting', cut some nice ashlar lines into it as its going off (firm but not yet completely set, like you would mono), use a limey weak mix rather than a 3 or 4:1 to be sympathetic to the building...

ive had a hosepipe up the the verge before today where the water penetrates, gets into the rubble cavity (or hollow cavity) and absolutely pees in the head of the window...

another example is the removal of box sash windows that origionally bridged the cavity and replacment with upvc that sit in the face brick thereby leaving the cavity open at the head...
water leaked into the brickwork above via bad pointing near the roofline ran down until it hit plasterboard and wel you can imagine cant you..

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