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The TV issue can be a bit complicated.
As km says, your current TV will probably not pick up the local Greek channels as UK TVs are set for PAL transmissions, while Greek channels are transmitted on the SECAM system. You might be lucky and have one that can receive both but you'll need to check first.
Of course, you would still be able to use the UK TV to watch your DVD/Video collection, or if you are planning to have satellite installed so, if you have the room, it might be worth packing them.