Hi OhPinchy
Please don't waste your money on the Dremel tool- it's a tool designed for modelmakers, hobbyists and small handcrafts. In fact it's quite good at these activities but it would take a long time to cut tiles with it. For this I recommend two options:
1. Buy a cheap 4" angle grinder for less than €40 and fit a diamond tipped blade for about €10 (cheaper quality DIY blade is fine for this). This will allow you to cut and shape ceramic and porcelain tiles. I bought a cheapy "Einhell" grinder for €20 in my local hardware store and fitted it with a cheap diamond blade and have used it to cut tiles, chase walls, cut out socket boxes, chase out for lead flashings etc. In short it's the best €30 I ever spent on a tool and it should last me for years.
2. If you have a lot of tiles to cut (especially porcelain, which must be sawn) buy a wet tile saw from somewhere like Argos. I bought their "Challenge" one for about €60 3 years ago and have found it to be more than adequate for the job. It comes with a diamond blade and allows you to make accurate, repetetive saw cuts in stone, ceramic and porcelain.
Whichever option you take (or both) buy yourself a good pair of ear defenders and safety glasses, the chips from cutting porcelain are like glass and the noise from the cutting operation is very loud.