Sprint 2000 Sprint ST engine tick

Hi all, I am new to the forum (have posted on the newbie thread) and have very recently bought a lovely condition black Sprint ST with 25k miles and a good history up to 19k miles. Here is the question, she has a very audible ticking noise that disappears when you rev her over 3k rpm, any ideas? She also makes a slight whooshing noise intermittently when ticking over, its not loud, just weird? I didn't pay the earth for her so am happy to spend a few quid if need be. Thanks in advance.........ps, I know these engines are not quiet by nature and there are loads of similar threads on t'net but none seem to describe my noise.

 

Thanks Steve, the last service in the book was 18k and she has now just turned 25k, took since 2007 to do 7k miles so I guess she could use a service!!! Does the 24k service include valve clearances? I can get a video on youtube to show the sound if it helps? Thanks again.

 

Many thanks.