We have the 1.3 95bhp model, performance, well remember its only a 1.3, you have to change down to 4th to do any over taking, its a bit slow off junctions, but once up to speed it seems ok, only done 150 miles so far and already have a engine management/emission light issue, so this might be clouding / effecting our experience thus far.
But not a patch on our 1.4 HDi Citroen C3, which was only 70bhp, we had a few years ago which went like, you know what off a shovel.
Leona, diesel engines are normally much tighter than petrol engines when new so they will loosen up over time and start to be more free revving and more powerful. However that is normally tens of thousands of miles.
The Corsa is a heavy little car, at 1400Kg in 5 door form it is the same weight as my 1960 Series Land Rover so a 1.3 turbo diesel will never be quick. It also weighs 250Kg more than the Citroen C3 so will definately be slower than that. If you look at the specifications the 1.3 turbo diesel engine doesn't achieve its peak power until a much higher rpm than the Citroen 1.4HDi unit and has almost no power at very low revs so again will feel slower to pull away anyway regardless of the difference in weight.
I've driven diesel cars most of my life as I do high annual mileages. I'd say 90% of the 200 cars I've owned have been diesels. However I actually bought a 1.4 turbo petrol Corsa E as the mpg from these little petrols is so good (especially on my motorway commute) that as LimeyUK says, the diesel is no longer cost effective even at the 15-20K miles a year I do. My 1.4T is doing nearly 60mpg on my commute and even managing 45-50mpg around town. The petrols give better performance when needed too.
My petrol engine is still only just loosening up at 6000 miles so I'd guess your diesel will need at least 10K on it before you start to see its best performance and economy.
Sorry to hear about your fault. You need to take it back to the dealer. Mine has not had a fault so far after 6K miles so they are all not all like that.