Don’t take this the wrong way, but you sound really confused with all things financial. I’d recommend spending some time on money saving expert and having a look at their guides on pensions, ISAs, etc, then asking some more detailed questions (maybe there rather than here), and seeing a financial advisor only as a last resort. You don’t really need to pay for an advisor to understand how ISAs pensions etc work.
When you say you don’t trust pension schemes to be around, are you in defined-benefit plans? If you are in defined-contribution schemes, it isn’t really different from holding any financial investment: it’s your money, not that of the employer nor of the broker where you hold the account.
How much is your monthly mortgage? Fixed, variable, or what? When does the rate reset? How much can you overpay before incurring extra charges?
How much are your monthly salaries net of tax, and how much disposable income are you left with after paying for food, bills, mortgage etc? Earning “decent amounts” can mean vastly different things to different people. How stable are your jobs? How much savings do you have? If one of you were to lose his/her job, how long could you cope before running out of savings?
My job pays well but is very unstable, so if I inherited £65k I’d probably use that money as a safety buffer should I be made redundant, unless I already had savings that could reasonably help me navigate a period in between jobs. For the same reason, unless I had huge savings, I wouldn’t use all of the £65k to overpay the mortgage: yes, your monthly payments would be reduced, but what if you’re made redundant? Let’s say that your monthly payments go down by, I don’t know, £ 250 per month. That’s great. But, should the worst happen and should you be made redundant, will paying £250 less per month be enough, or will it be best to pay £250 more but having tens of thousands of savings you can dip into?
Note there is no ‘right’ answer: that’s what I would do in light of my job situation and my paranoia, eh, prudence – it doesn’t mean that a different approach is wrong!
Also, don’t forget that the alternative to overpaying your mortgage is not only keeping the cash under the mattress – you can and should invest it. In fact, you should compare the ‘cost’ of alternative options: how much you’d save by overpaying vs how much you’d get by not overpaying and investing the cash somewhere else. If you want to invest in cash saving accounts, you’ll almost inevitably end up receiving a lower interest than that on your mortgage; if you’re willing to take a longer-term approach and to invest in stocks and share, you have the potential to earn more than the cost of your mortgage over a longer horizon, but the value of your investment may easily go up and down over the short term.