I'm not sure you do need financial advice for that amount, even if you do, you need to think first about what you want, to get the most out of it.
You say that you don't think you'll get a mortgage, but that depends how much flats cost where you live. There's many places where £75k would pay for half to 75% of the cost of a flat, even when keeping back, say £10-20k for fees, moving costs and any work you might want to do. And you could well get a mortgage for the rest on what you earn - payments might only be £2-300 pm.
Any money you put away for a pension is inaccessible until your late 50s so don't do that unless you're sure. It will also take several years to get all the money into a pension, even if that' what you decide to do.
For any money you invest rather than save, you also need to consider that you might not be able to touch it in the short to medium term without losing money.
It's likely we're going to hit a rocky patch economically, which might mean that property values drop and you're well placed with £75k to get a flat for around £100-120k for example.
Definitely open a LISA and just put a small amount of money in it. Then after a year you'll get a bonus if you do decide to buy.
Then put in the best instant access account - I think you can get nearly 2% now, while you decide what to do with the rest.
If you do get income based benefits, it's right that you might lose those with an inheritence, but not any that are due to your disability, as they're not means tested.