it does seem strange that it’s not available yet. As you say, it’s available in the new Ibiza (FR model), but only with a manual gearbox. All the information about the forthcoming Polo R-Line with the 1.5 Evo engine has stated it was to be DSG-only in the Polo, so maybe it’s unavailablilty is something to do with the combination of this engine with DSG transmission? However...........it’s interesting to note that the 1.5 Evo engine is available in the current Golf GT (with 130 and 150 ps power outputs) and the Golf R-Line (150 ps power output) models with both manual and DGS transmission options, so if they can install the 1.5 Evo (150 ps) with DSG transmission in the Golf, why not the Polo?; maybe it won’t physically fit!

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This is unlikely to be the reason, as VW fit a 2 litre engine with DSG transmission in the Polo GTI. I’d guess it’s probably more to do with something like CO2 emissions, and VW having ambitions to achieve some ‘magical’ low CO2 figure that makes a Polo 1.5 DSG R-Line an attractive proposition to prospective customers who put a high priority on such things.
If and when a 1.5 Evo engined Polo R-Line does appear, it’s price point relative to the GTI model will be interesting. Currently, the 1.0 (115 ps) Polo R-Line with DSG has a list price of £20,280, compared to the Polo GTI’s list price of £21,140, so the GTI (DSG only at present) is only £860 more expensive. Interestingly, Seat charge an extra £1,050 for the 1.5 Evo engine in the Ibiza FR over the 1.0 115 ps engined version. So, if VW were to apply the same price uplift of £1,050 to the 1.0 115 ps DSG Polo R-Line for the 1.5 Evo engine, it would have a list price of £21,330, making it £190 more expensive than the GTI.
I know that the GTI isn’t for everyone, but it looks as if the 1.5 Evo 150 ps Polo DSG won’t be particulalry good value compared to the GTI.
You could always ask a VW dealer when the 1.5 Evo engine will be available in the Polo, but I wouldn’t be surprised if dealers don’t know either!