Decided to remove the tank the following day as fuel pump was very noisy and no fuel flow. Removed low pressure pump to find pump housing and strainer fuel of slimy deposits. Also found deposits in base of tank. After reporting to customer decided to renew fuel pump which comes pre assembled in new tank (note new tank comes less 1 breather and modified filler cap and wiring loom were also required). After reassembling system primed and vehicle started with no trouble. FIXED !