As
@timselectric said, about 3,564 posts ago

similar in price. Deye is a bit cheaper than Sunsynk for equivalent model - so like 1450 GBP for the 8kW hybrid vs about 1,600 GBP for the Sunsynk branded one.
You say "maybe they sell side by side"... that would be my understanding from seeing them both advertised over hear and seeing that both brands have inverters with approval to connect to the grid. BUT, if they do officially sell side-by-side, why does the Deye screen-of-death tell UK users to contact Sunsynk. Something doesn't add up to me.