(Reuters) -Spain’s Santander SA has begun the process to find a replacement for Chief Executive Officer Jose Antonio Alvarez, according to a source familiar with the matter, gearing up for a change at the bank’s helm after seven years. The bank’s board, however, has not provided a time-frame for the search, the source added. A number of the bank’s top executives are among candidates to replace Alvarez, several bankers and financial sources in Spain told Reuters. Among them are Santander’s regional head of Europe Antonio Simoes, wealth management head Victor Matarranz, CEO of Santander Mexico H…