B5.5 tyre size

[nightshade]

Guys,

I need a set of 4 tyres. My 2003 TDI estate has 206/60/15's on that came with it. When I use tyre sites and my reg to find the right tyres, nothing comes up.
I had a look using other reg numbers of cars I could se that were the same age and had the same alloys and they all came up as 195/55/15.

Does anyone know why they'd be different? and do I have the right tyres on my car?

Many thanks