You are privaledged! I have been flying our Chippy, G-BCSL, since 1979 and it is my favorite aeroplane.
The Chippy is not at all difficult in any way - service pilots soloed it from zero flying experience in very few hours. But it is demanding to fly it
well, which I hope is your aim.
If you can taxy it consistantly accurately and well, you can fly it. Coming from the PA28 you will be amazed at how aeroplanes can (and should) handle once you've flown a Chippy - you will not want to go back to the Cherrytree for pure flying fun. It will bore the pants off you after the DHC1. But the PA28
is a practical A to B tourer, which the lovely Chippy, with its 18 gallons of fuel, no luggage space, and limited nav facilities is not.
These machines are becoming ever more difficult to keep in the air due limited spares availabilty - so try not to break anything. And make
very sure your instructor emphasises and trains you in sympathetic engine handling that the vintage Gipsy requires if it is to live to a reasonable number of hours.
But most of all - enjoy!
Here's me in the front seat of our's (care of the excellent DamianB) having just started up at Woburn deer park at the dH Moth rally last August, for return to Liverpool John Lennon where we are based:
SSD