oh I've just re-read the thread. It's to say thank-you.
So then no gift. Just say 'thank-you ever so very much' in person.
A gift is over-generous or even over-doing it unless it's Christmas or Birthday or he's specifically asked for something he likes of yours.
What I do if a gesture really must be made and you're sending it in the post because you'd have to travel to see him is, and this costs £1: Make a daft card with all stars and roses and kisses and thankyou's and then spend the £1 on a luckydip lottery ticket, shove that in the envelope, stick a stamp on it and if you don't hear back, well don't be so generous or grateful next time...
madly
xLinda