PD Injectors - Talk to me!

Picked up the Roomster from UNIT18 having had a replacement clutch fitted.

Alistair noted that the 'kangaroo' effect from 3100k rpm upwards in 3rd is likely down to a faulty/failing injector. So my queations are as follows:-

1. Is there any long term damage from running with a faulty injector?
2. Replacement/Upgrade to PD130/PD150 injectors - Would my remap need a tweek? or would they simply flow at thte rate the map is 'asking for'?
3. Is there a chance one or more may be clogged and is there a 'Try this first' option before replacing the injectors? Injector cleaner or the like?
4. What/How can I log some info with VCDS to confirm it is an injector at fault?

Thanks in advance J5