Hi Marts500, welcome to the A2oc.
The A2 was my first diesel. I drove the petrol and diesel cars back to back before deciding and once I got used to the agricultural engine noise at slow speeds I definitely preferred the drivability and more relaxed nature of the diesel. The £35 road tax is also nice but you probably pay more for the diesel in the first place so in the scale of things its not a big plus point.
I would agree with your observation that the diesel engine seems to suffer less problems. Ignition coils and emissions related warning light issues are often mentioned on petrol models.
As Rob Earl said, test drive both models, preferably more than one of each, before deciding.
If you have not already noticed, we have a section in the forum with copies of three model year brochures which give accessory info, specs and prices.
Cheers Spike