[Getty Images]Hull City, Ipswich Town and Coventry City have all invested significantly this summer in their respective bids to retain their Premier League status.The three clubs have spent a combined total of about £400m, with Ipswich breaking Sunderland's £160m record for the most money spent by a newly promoted club in the Premier League by £11m.But it is the Tigers that have been the most active during the summer transfer window, signing 18 players in this window - six of t