The 3p connection charge is for their landline product (still the cheapest around I think you'll find).
VOIP charges page states:
"Rates are in pence per minute and include VAT. Calls are rounded up to next minute.
No callsetup/startup fee!"
As for recieving calls not really a problem for those who already have a land-line but if you want an incoming VOIP line then what's stopping you using the free part of Skype?
Saying that it looks like they are shortly to provision customers with new VOIP numbers
http://www.voipcheap.co.uk/en/free.html