ARP Tunnel Network K1A [????- ]

Elizabeth Ride found this mention of ARP tunnels in the BAAG document KWIZ 72/23. From the description of the location I think it was this network they're referring to:

3. Ammunition:

The Japs have stored large quantities of ammunition in the air-raid tunnel, at the foot of the hill near the Electric Power Sub-station, on the EAST side of NATHAN ROAD. The exact location of this ammunition dump so far as can be ascertained is 20425721.
(6 Sep 44 - Graded C2 - Source: Halo (BAAG)).

Comment: Storage in a tunnel here previously reported in KWIZ 44/29/II (c).