Can anyone assist with a report that extracts the External ID field in the CRM

Question

I have a membership system where the client has imported 3600+ records some of which had the Eternal ID ('Your ID field on the import file) set and some don't.
The trouble is I need to update all the CRM records and can't import the changes as I don't know what the original external id value is. Business Catalyst support advised that they can't include this field in any report (don't get me started on that...) and I am now desperately in need of some way to get that data which is on the file and is critical to any further updates via the import files. I would delete all the records and start again except that there is no bulk delete option in BC CRM - yes you can do it in products but not CRM or Web Apps...!!! The only option available in BC is to delete one screen list at a time but then I have the issue that this matter does not relate to all CRM records - only those whio are members of a secure zone.
My need is urgent so any assistance free or otherwise would be approeciated and the solution needs to be one that enables me to run such an export on an irregular basis.

Answer 1

OK... thanks to those who offered assistance and I now feel somewhat a goose but then not altogether.
BC in its usual style of help documentation, are not at all clear in their explanation of how the Unique Id (which is actually the field 'External ID' in th CRM under the Misc section). Below is the description extracted from the import template
The above columns represent all the available columns that can be imported using the standard contact import feature. Columns do not need to contain information but they must be present on the page, especially if a proceeding column contains information.
If your organization uses its own unique identification number to differentiate between customers then use the Your ID column. If a value is present in this column then it will serve as the unique identifier. This means if the contact was previously imported and it is being re-imported then his or her details are updated, otherwise a new contact record is created regardless of whether a similar contact already exists in the system.
If the Your ID column is not used then contacts are generally identified by their email address. The minimum requirement to import a contact into the system is that either Your ID, Email Address, Fullname, firstname or last name must be present on a single row. If these values are missing the the row is not imported and the import will move to the next row.
If you don't provide Your ID nor an email address and only a name then the contact is added each time regardless of whether a similar one already exists in the system.
Now my understanding is that if you have used the Your Id then being the unique identifier and as such all future imports would have to use that... Well no this isn't the case at all.
If you import a set of records that all use the Your Id you can simply update those same records with just the email address - you don't need to Your Id or External Id at all!!!  So what is the purpose of this field at all? I have no idea myself as it can't be reported, it can't be exported, it can't be referenced - in fact the only way you will ever see it is to open the CRM record and expand the Misc details and buried at the bottom you will find it. Now that is what I call an undocumented feature !
So end of it all is - my concerns all proved baseless and you don't have to concern yourself with the External / Your Id field no matter what the customer does.
My advice - forget this field exists and don't bother trying to use it unless you might happen to be interfacing into some 3rd party system through PAI's as this seems to be the only use I can think of for it.