As promised my report back on this small radio.
First the intermittent cutting out was down to some old corrosion on the battery terminals. Now all clean and shiney.
The interference on 909Khz was in the end down to a tweek or slight re alignment of the RF/IF stages, which I did by ear. Well I could n't be bothered to get my signal generator out for this job
Now all the stations on all 3 wave bands are reasonably clear and much closer to where they should be on the dial than when I started out.
Not the nicest of jobs I have undertaken but at least you can take the set apart easily. I reckon it dates back to the 1980's. Some of the newer sets that I have seen are far worse.
Now I can take the Realistic back into the office for very occasional use and bring my Bush Sandpiper back home. After all if the Realistic gets nicked thats the thief's bad luck
. This would be a different matter with my Bush Sandpiper of course.
Many thanks for the helpful suggestions.