Find Director Emails For 23k Companies

I have a spreadsheet containing 23,133 UK-registered limited companies, sourced from the public Companies House database. For 99 % of them the director’s full name is already listed; what I still need is the best email contact... (Budget: £250 - £750 GBP, Jobs: Data Analysis, Data Cleansing, Data Collection, Data Entry, Data Management, Email Marketing, Excel, Lead Generation, Research, Web Search)