Shopping list (help with filtering formulas)

Hi all.

I've made myself a spreadsheet to help with meal planning and also generates a shopping list for me.
But I feel like it could be improved.
The only bit I'd like to sort out is the part that generates the list.
I've inserted a simple function that adds the ingredients which have been selected as needed, which is as follows:

=IF(C4="Need",B4,"")

Then to sort out the blanks, I've added a filter and de-selected the blanks.

The issue I have is that I'd like to sort the list alphabetically, but when I do, it doesn't seem to like it and I get loads of #REF! errors.
So I just copy the list over and then sort it alphabetically, but this just seems like a bit of a bodge.
I've attached the file for anyone to have a look at.
Does anyone have any ideas?
Also if anyone has any tips they'd like to add for any part of the spreadsheet, I'm open to suggestions.

Thanks
Jim

Administrative Note:

We would very much like to help you with your query, however the thread title does not really convey what your request is about.

Please take a moment to amend your thread title. Make sure that the title properly explains your request. Your title should be explicit and not be generic (this includes function names used without an indication of what you are trying to achieve).

Please see Forum Rule #1 about proper thread titles and adjust accordingly. To edit the thread title, open the original post to edit and then click on Go Advanced (bottom right) to access the area where you can edit your title.

(Note: this change is not optional. No help to be offered until this moderation request has been fulfilled.)

Are you amenable to a VBA solution? And as a point of interest. It is the start of a long Holiday weekend in the US. Many of my countrymen are not back at work until Monday. Patience is a virtue.