They are right in saying all you need is an ICAO PPL. There is no advantage to holding a JAA PPL. However, you'll still need 150hr TT before commencing the CPL module, during which time you'll be well advised to get the night requirements, amongst other things, done. Otherwise they'll have to be added to the CPL module.
So whether you complete the night within the PLL or after doesn't matter & you will not save any money. You've got to pay for 150 hours one way or another, unless someone will lend you their aeroplane for free after you have a PPL.
The other thing that many people overlook is that your CPL and later training will be much more difficult (& therefore potentially expensive) if you spend the 150 hrs boring holes in the sky. Unstructured hours’ building is a mugs game. That's how the 'cheap' schools advertise cheap Modular ATPLs (loads of hours solo VFR in a cheap ac in a cheap environment like the US costs little). In practice people often need more time later, to overcome the effects their poor early 'training,' when it's costing them £350/hr. That's what gives the modular route a dubious reputation in some quarters.
A properly constructed modular training is better than an integrated course, as it involves more training overall, and less % can be spent on limited value VFR cross-country training. A poorly constructed one is considerably worse. IMHO
