Oil caps & hose kits?

I've found some oil caps that I actually like [ HERE ] but what can fit in the rover k series? Is there any other car with the same fitment? I haven't actually looked at this in much detail in my engine so I'm not really sure what's involved and why there are different fitments but if anyone knows one from another car would fit...

And does anyone have a list of some hose diameters? I'd like to buy in some silicon hoses and cut them to size but don't know what thickness to get...

Thanking ye kindly.
Liam

Oh, and they also sell battery terminals / covers and a grounding kit - I think it could look quite nice but am I better spending my money on something else?