I worked on the Pier for quite a few years, so have a good knowledge of how the maintenance regime works (or how it used to, rather).
The figure you mention (that is now up to £120,000 a year roughly) is pretty much all taken up with repairs to the steelwork. Unfortunately, very little is left over for other repairs and maintenance. Take a close look at the kerbs as you walk up and down the pier (the wooden bit the railings rest on)and you'll see that some of them are in a shocking state, with one or two bits completely rotted away. Take a look at the photo attached - it's a section of kerb that was marked out with yellow paint for replacement two years ago due to the fact it is rotten through - the work has still not been carried out and that section is deteriorating further. I'm afraid that's the reality of the situation.
Of course, the £120,000 spending is great but it's not investment, it's just routine maintenance. Investment is when you build new attractions and facilities to get more visitors spending their money. I can't recall anything significant in many years. If we're honest, the pier looks tatty and its attractions are tired and run down.