Seriously, I would want to ask some very pointed questions about "TR6 SU carbs", since AFAIK the factory never put SU carbs on a TR6. In particular, who chose the components to make them suitable for a TR6 ... the float bowls look awfully close to vertical to me, while the TR6 needs inclined bowls. Those also look like "waxstat" jets, which are notoriously troublesome (on cars so fitted, which again was never a TR6).