found and dealt with 3 of the 3 suspects, in the process found a 4th - seep from under the port side shroud base. I won't be touching that until the autumn. Thanks for all the suggestions.
I used to have a Sadler 25 which used to collect water in the bilges, I tried everything, re sealed the keel, re sealed all the windows and hatch but still no better.
We came back from France in a good force 6 one day and when I looked down below the charts were floating about in the cabin, my wife said not to worry as the Sadler 25 was unsinkable, I replied no that is the Sadler 26.
I finaly found the answer, the water was getting in from inside the anchor well where it joins the deck, there was actually a half inch gap there at the top.
I put epoxy tape over the gap and we never again had a spot of water inside the boat.
By the look it would appear that the boat was built like it so I would think that most other Sadler 25's would have the same problem.
I had a boat with a Volvo engine ( saildrive 13hp, I forget the model, memory is kind ) - the core plugs began to fail when it was about 12 years old, first I knew was when one with a special sense of humour corroded through when motoring in a calm at the top of the Alderney race, spouting water into the engine bay bilges; as I'm not a fighter pilot I'd never spun out of control at such speed over the ground, what 'fun' !
A chum with araldite fixed it and we waited for it to set ( 'rapid' was but a dream then ) while people going past busily ignored my request for a standby & tow, b******ds...
Volvo stern seal life: Volvo say replace after 5 years but some seem to be OK for a bit longer. Should not leak at all, except when burped after taking ground when a few drops should come through. Once it gets tired it will weep a bit, indicating should be replaced as soon as convenient. Check P bracket cutless at same time, as that may be worn as well.
Water pump; if it's anything like the Yanmar variety, a leak indicates seals (and possibly spindle) need replacing, as in soon, although do first check the cover plate is sealing properly.
Even the faint possibility of a leak anywhere in raw water cooling system is a very good reason for closing seacock when leaving boat. (You knew that, of course, but there are some who apparently don't, a boat in our club nearly sank that way.)
Another source of water: log impeller and housing for same. Mine used to leak after a hard beat to w/w, also when on exposed moorings in a strong blow. Replaced O ring seals and now seems OK.
Plumbing; fruitful source of minor leaks, just like home. Two I found were: pressure-sensitive switch for fresh water pump (a rubber seal had become un-bonded); and a shower-head type outlet had a tired O ring and the resulting leak had water dribbling down the outside of the pipe (instead of into the sink) and thus into bilges.
When I bought my Sadler 25 (fin), the bilges were as dry as a bone. After some serious and prolonged rain, I had some wetness in the bottom bilges. I tasted it, but it was so horrible, I couldn't be sure it wasn't salty!
I mopped them up with old towels and they've been dry ever since. Still get a thimble-full in the engine bay sometimes.
This is just as well, since the hose from the bilge pump was missing....I still have to replace it....