How about twin and screen like this http://cpc.farnell.com/pro-power/mic0036/balanced-microphone-cable-black/dp/CB13305 fed through garden hosepipe and buried with tape cover http://cpc.farnell.com/_/barrier5001540752/non-adhesive-yellw-blck-tape-barrier/dp/HE30673?in_merch=Products%20From%20This%20Range