Hello, I am a Chinese citizen holding a Chinese passport. However, I possess a Spanish resident card, allowing me to freely travel within the Schengen area. I recently purchased a flight from Spain to Romania, and on the return journey, I have a layover in London. I was informed that I need to enter Britain to collect my luggage and undergo check-in again for the connecting flight within a 4-hour window. Do I need to obtain a visa for this?