Hi again, thanks for the welcome everyone.
As advised I have thrown out the sunfilter, it was cracked - an old floppy disk would have been more effective!
i have read another SGL thread on the RET50 and everything thing mentioned there is true. (So I may end up buying something better)
The viewfinder is misaligned and seems impossible to adjust, I think someone superglued the screws, but at least I know by how much and where to aim.
Moon looks ok, but can’t seem to focus on a star clearly, and don’t want to try collimating until I can find a manual for this specific type.
I look forward to reporting any progress if we ever get clear skies now the snow has arrived in Switzerland.