Throttle housing inlet/return hoses replacement

Hi All,
I've had some problems with losing coolant for a while, not much, just having to top it up with a drizzle every few weeks. Recently I noticed that what the manual refers to as the 'throttle housing inlet hose' and the 'throttle housing return hose' are both perished and coolant has been draining out around the immediate area. I'm obviously looking to replace them but I'm struggling to find anywhere that stocks them, unless they're known as something different??? Does anybody know anywhere that might stock such items?
Also, if anybody has gone through this process, does it mean a full drain of the coolant system?

Many thanks

Any decent landy parts stockist should know what you mean , failing the , ring your local dealers parts dept and get there price AND the part number , then ring the aftermarket boys , Landranger , Craddock , paddocks ETC . Remove pipes , fit new and bleed system , as there at the top should'nt need to much refilling .

Excellent advice, thank you very much.