In reply to sloper:
Whoever said ask them was on the right lines. If they were *very* observant I doubt they'd invite a gentile for supper.
But...
Firstly wait until the religous holidays are over - Rosh Hashanah (Jewish New Year) is just starting. There's a lovely multicultural list on the Birmingham Council web site! So, BTW, is Ramadan and one of the Hindu festivals.
http://www.birmingham.gov.uk/GenerateContent?CONTENT_ITEM_ID=1183&CONTE...
For food:
http://www.kashrut.com
> I'd suggest something like fish with herbs and lemon (no butter),
Make sure it has scales & fins. Shell fish & eels are not kosher. Herrings & salmon are certainly OK. So is mackerel & tuna - and so apparently are goldfish! They are a kind of carp at least for kosher classification.
> duck with cherries, some cheese.
Oops - meat & milk! Think duck still counts as meat... And apparently what is and is not a kosher bird is a apparently bit complicated...
How about going fish & veggie and maybe a little cheese? Gets round all the stuff to do with meat, and with mixing meat & milk.