Extracting a text string from a URL, almost there

Dear Wizards.

I have a problem that has just plain stumped me continually.

I have a file with URLs in it (see attached). I want to extract the a string that starts just after "id=". I got this first part taken care of with the following formula:

=SUBSTITUTE(MID(A7,FIND("id=",A7)+3,9),"/","")

This works great when the extracted text is a total of 9 spaces. For example if part of the URL were:

italy ca. 1880 /id=f_1097688/ref=lu91711097688/asking

The formula returns perfectly: "f_1097688" Just what I want!

But if the numeric part of this ID is shorter than 7 characters it returns to the 9th.
If part of the URL were:

white polka dot blouse/id=v_62437/ref=au120401247688/

The formula would return, "v_62437r"

I have tried altering the formula like this:

=SUBSTITUTE(MID(A7,FIND("id=",A7)+3,9),"/r","")

No luck.

To make matters tricky I have ids with 1 through 7 numbers. More simply put I want everything after "id=" and before "/"

Thank you so much for your help please see the attached spread sheet for sample data.

Tim

Great minds think alike!

Thank you very much gentlemen this I has been very educational comparing your two takes.

Thanks again!