Few options
Darkside - ive used these for parts no experience of mapping
Shark - Did my Stage0,Stage2 and Stage 2+ mapping on my old PD170, it made a realistic 228bhp
CC-Tuning - they are a sponsor on another forum i Admin on (TDISport.com), i have no experience of Chris's mapping but alot of the people on the forum are happy
R-Tech - No experience of them but from what ive seen Niki is a master of his trade
May i also throw RS Tuning into the mix, My friend has got a PD170 Golf running a Hybrid Turbo,WMI amongst the other usual Stage2 DPF delete mod's hes recently swapped his Shark mapping for RS-Tuning, it made 3bhp less peak power but made 25bhp more through the rev range and now goes a hell of alot better (the Shark mapping was good)