Is there any difference between a Low Current Engineer and EXtra Low Voltage (ELV) Engineer?

There is no difference. Both are same. Its just the designation given by different companies. 

According to the British Standard for building service, extra low voltage (ELV) is defined as any system operating in an voltage not exceedingV ac (orV ripple free dc). ELV system is a wide range of services in the building that can be provided by us. In terms of the functional approach, it can be categorized into9 main sub-systems: SMATV / CABD System (Satellite & TV receiving and broadcasting system) Public Address System Closed-circuit television (CCTV) Surveillance System Security Burglar Alarm / Card Access Control System Radio Paging and Walkie Talkie System Home Automation System Radio Frequency Identification System (RFID) Biometrics Security System Watchman Tour System