I'm 100% right!! Contact the consumer rights people (can't remember the official name) or a consumer specialised solicitor. They will confirm what i'm saying is 100% legally correct.
The only way they can void a warranty for removing a factory fitted plug top, is if the connection method doesn't comply with the Codes/Reg's of the country concerned. eg, a dangerous DIY lash up tape job, or connected (via plug top/FCU) with maybe the polarity reversed etc!! ...lol!!
It is normally the authorized service agents that come out with all this crap, not the actual manufacturers. The only reason manufacturers provided a plug-top (moulded or otherwise) in the first place, is because of the EU regulation stating that all appliances must be supplied with a suitable plug top corresponding to the country of final destination!! Contacting the manufacturers direct, or as a last resort a solicitors letter to the service agent etc, will always change their mind pretty dam fast!!
An appliance manufacturer or it's agents cannot circumvent recognised/official codes/Regulations within a given country to suit themselves. They can recommend or even stipulate RCD protection in some cases, they can stipulate a minimum cable/flex size, installation positions etc, but that's about it... It's the same with BS 1362 fuses, it's often stated here that manufacturers state the appliance must be protected by a such and such rated fuse. This can only apply to the size of flexible cable, not to the appliance itself!! BS 1362 fuses are not and never have been designed for the protection of appliances!!