The analysis concerns continuing qualifying business and the qualifying organization, not a universal requirement to keep the same product line. Explain the actual goods or services and the entity providing them.
Distinguish a changed activity from an inactive company
A genuine operating change needs evidence. Do not treat company registration or an unused office as proof of regular, systematic and continuous business. Work through the change one record at a time.
First, the last month in which the discontinued activity was actually performed, evidenced by an invoice or a delivery record rather than by memory. Second, the first month of whatever replaced it, evidenced the same way. Third, anything that ran across the gap: a maintenance contract, a service subscription, a retainer that continued to be billed.
That third category usually decides the file, because it separates a company that changed what it sells from a company that stopped selling. The qualifying year abroad must be one continuous year of full-time employment with a qualifying organisation inside the three years preceding, so date these records precisely; an approximate month at either end of that year is the weakness a reviewer finds first. Hypothetical example: a distributor of machine parts ends its catalogue sales but keeps billing a scheduled restocking service, and the recurring invoices carry the continuity a summary letter could not.