The Mk4 is a massive improvement over the Golf Mk3.
If you have a Mk3 sell it and buy a new one!!
With the chipped engine, performance was increased significantly (The 110 was not sluggish in its original form!) but the best is yet to come; No matter how I drove I could not seem to get below 50mpg.
Under "normal" driving conditions, I averaged between 54 and 62 mpg.
Best overall journey; 69.9mpg average speed 44mph.
Best journey MPG; 70