Who makes the best scart leads?

And can i get a splitter box for scarts that also has an imput for the tv aerial?

Check out QED. Their scart leads (and many other products) regularly win awards for their quality.

They also make splitter and switch boxes. Scart Leads:

Scart leads come in various brands and qualities, this page will help you to identify high a quality cable and shows our range of high quality leads.

Choosing a Scart Lead

The Signs of a poor lead

When choosing scart leads for home cinema, home theatre or television there are some important things to consider. If you have a large screen television such as a plasma tv, rear projection tv or a standard CRT type television with a large screen, you are really going to notice the problems caused by poor quality leads. The most common problem with low end leads is picture ghosting, this is caused by poor shielding of the video conductors within the cable, poor shielding will also result in crosstalk between the audio channels. Shielding is key to getting the best audio visual performance from your home cinema or home theatre system.

The OEM supplied Scart Lead

Most consumer DVD players, DVD recorders, VCRs, Digiboxes, Freeview boxes, Sky+ (Sky Plus) boxes etc are supplied with an OEM scart lead. The fierce price competition with these types audio visual devices often means the manufacturers are trying to save every penny, in so doing it is items like the lead which tend to suffer. The typical OEM lead is a far from a glamorous looking item, usually identified by nickel plated connectors with plastic connector shells and a thin cable joining them. The majority of these leads perform as they look, very poorly.