Arch Lector
War Altar
Mace of Helstrum
Van Horstman's Speculum
Heavy Armour + Shield
The point of the VHS is to take away the attacks of any hero challengers, and lower their strength to not auto-pop the chariot. If their values are high enough (such as Chaos Lord, Greater Daemon, etc.), using the stats may be beneficial. Alternatively, if the stats are only ok, but better than the Arch Lectors, still take away their attacks and strength, but use the mace to destroy them completely.
The great thing about this combo, is that its not necessarily a one trick pony - it is two. If for some reason one of your magic items is destroyed or nullified, you still have a back up. What's more, the VHS is ideal for challenges, the Mace allows the Arch Lector a fighting chance against Big Nasties, as well as monster base sized models, and S10 also allows him to pop chariots if he so wishes. The "Cannonball on a stick" (Mace of Helstrum) is very versatile, and the VHS is just like another form of save against scary characters for the Arch Lector, which allows him to use the Mace.
The armour is low, but he still has a 4+WS, and the ability to cast to different bound spells to heal himself.