Two Pick Up Locations with One Inventory Location

[Bees1]

Hello - We are small business and we don't manage our stock levels via Shopify however we are setting up a click and collect service using shopify in which we will manually transfer the purchased items to the selected pick up location as required.  The stumbling block I am coming across is I have uploaded all the products via the product.csv file format and I have set up two locations both of which are active in the settings, however upon checking out it only lists the default/first listed pick up location and not both.   I don't want to set up complicate inventory spreadsheets that forms no value to our business to get round this.  Upon much searching I have found a workaround solution that only appears to be available on the shopify app rather than the website user interface where individually for each product I can open click edit on the 'Inventory' section (note I already have the inventory set as 'Not Tracking' via my .csv upload) then I can click on 'Edit Locations' in the 'Quantity' section and then I can tick both locations.   And this works when I modify each product individually. However I loose this pick up option if I happen to reload an updated version of the .csv file.

My question is how can I get the .csv file to automatically select all active locations for each of my 100+ products or alternatively how can I do a bulk edit for all live products as this option is not available from what I can see  in the bulk edit?

Any help would be gratefully received.

Thank you very much