recently acquired a rangerover 2000 model 2.5td hse had a flat battery charged the battery used the eka code and resynched the key fob went to start the engine only to be greeted by a series of warning messages and a clicking followed by the lights flashing and the horn honking wouldnt turn over so despite hours of research found out that it could be as simple as not enough power in the battery has anyone else had this and to replace the battery what is the cca needed as the old one has no writing or stickers on it and everything ive read so far differs any help would be appreciated and please no nasty comments thank you in advance