Hi, they are the same part number for most RHD e39 unless they have some really obscure options; 12 42 1 436 885. Part #1 below:

http://bmwfans.info/parts-catalog/E39-Sedan/Europe/525i-M54/R-A/nov2002/browse/engine_electrical_system/battery_cable/



Price: € 194.60 EUR (on www.carparts-pros.com, add €17 for delivery, plus €5 for PayPal)