The pilot reported that he was ferrying the helicopter back to the company base after maintenance via a helicopter landing site near Jacobs Well. At approximately 200 ft AGL during the approach, the cyclic control became restricted in that the pilot was unable to introduce any left cyclic control. The pilot said there was insufficient control available to conduct a safe landing. Eventually, he was able to force the cyclic control free and land safely. After landing, the pilot consulted the maintenance organisation and confirmed that work had been carried out under the front seats. The pilot then removed the front seats and discovered that the cyclic control had been jammed by a radio control box. The box had not been re-installed corrrectly after maintenance. The matter has been referred to CASA airworthiness at Brisbane for further investigation.