That bumper part you have there is the top part. The upper on the edition 30 is no different to the one on a 54 Reg Golf SE.
Its the lower bit that VW prices that differentiates it from the other models. It is very expensive.
The Dealers you spoke to have either been a bit clumsy with the pricing, or a bit cheeky for charging extra. I didnt think they were allowed to inflate ETKA's (vw part system) pricing.
Anyhow, it should be £388.30 including VAT.
Your better off scanning ebay to see what you find!