Not qualified in anyway - thoughts just based on experience:
Are you already maxing out your tax free pension contribution? (You say you have a scheme but not how much you contribute). This is by my understanding by far the most beneficial place to put money, as the government will contribute your tax rate. Judging from your disposable income I assume that would mean at least 40%. Ie, you pay in 5 k, government immediately gives you 2k..... that's an amazing return. It can then be invested and also generate investment growth returns. Only catch of course is money is not accessible- but that's perfect if your priority is security and responsibility.
Between mortgage and investment, really depends on your mortgage rate v the potential gain you can get from investing in different stuff (dependent on your risk tolerance).
Also depends on your life plans..... when you might want to cash out investments, and whether ending your mortgage sooner is important to you.
Yes financial advisors can be good - but be careful - the ones that get commissions on products cannot generally be trusted to give unbiased advice.
I personally steer clear of investment properties, just because it's a real life hassle and time suck.... finding properties, renters, dealing with complaints, repairs, that's a serious cost, compared to sticking it in an electronic fund and seeing it grow..(hopefully!).
If you do invest then do 20k each a year in ISAs - you can get a stocks and shareS ISA and your gains will be tax free. You'd have a bit more left over to do something else with.
When you do invest, unless you are very financially astute and have time to monitor everything, just stick it in diverse tracking funds that are spread out globally across different industries and company types... then leave it! There is really interesting research that the more times people check their portfolio (ie more actively they try to 'play the market' the less money they make! Also don't invest like this if you need your money soon (eg to upsize your house) as you may be forced to sell when the market is down.
Hope this is useful.