Quite an easy job for a beginner to tackle.
Hardest part would be getting the old system off.
Although I'd recommend seeing if a local exhaust shop could fabricate you a system rather than buy one off the shelf.
For both my 1968 Plus 4 and 1971 4/4 a complete system fabricated in stainless and fitted to the car was much much cheaper than buying one off the shelf.
Think it worked out at 150 quid for the silencer and 70 quid for the tail pipe
Arwyn