Urgent: 5N for £299 here in UK - should I buy?

I have found a shop display (but in good condition) 5N for sale at a well known quality retailer for £299 with the stock 18-55mm.

Although longer term when budget allows I hope to consider the 6 or equivalent, would a 5N still be good? I plan to use it for portraits, 1080P video blogging, family shots and video and indoor shots of businesses for high quality websites.

Also, I read about a clicking sound. Is that cured now? Is there a serial number to look out for?

Thanks!

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