Pinewood Studios was the studio complex where the UK show Dragon's Den was filmed before moving to Manchester.
The early British series used Pinewood Studios in Buckinghamshire. The site is one of the United Kingdom's best-known production locations and has hosted a wide range of film and television work. Its association with Dragon's Den concerns the programme's earlier production period, not its later Welsh or Manchester arrangements.
Production subsequently moved to Roath Lock Studios in Cardiff, which is why Cardiff is strongly associated with the show. In later years, filming moved to Manchester. These changes can make location questions confusing because several studios have hosted different phases of the same long-running programme.
The question asks for the earlier studio complex, not the city where the programme is filmed in a later period. Pinewood Studios is therefore the specific historical location required.