With so many unknown factors, it's hard to guess the future. Did you go to uni, do you think you're kids will be bright enough to go even if you didn't; are you earning enough to save about £80k over the next 18 years.
I know this will raise a few hackles, but Gordon brown did a disservice to both youngsters, and to business, in trying to push at least 50% of students into university places. It was, and always should be, for the brightest students, and just sending anyone there, can give the underachievers a false sense of their worth, and misguided view on life, and leave them with a debt for 25 years. If there were less students going to university, then the government could afford to go back to the old days of giving student grants. As it is, it's reckoned that the system is going to collapse in a few years anyway, as not enough is going to get repaid.
A masters in golf course management will force you to stack shelves, and as a Chris Woodhead (former Chief inspector for schools) said after he got disillusioned with the education system, don't bother with any course that has "studies" in it's title. If the degree isn't going to get you a damned good job, then don't bother with it.
Loans get written off after 25 years, or when you reach 65. The current interest rate is 0.9% on the student loan, and you start repaying 9% of your salary when you earn more than £17335, so at that level, you'll be paying it off for the next 25 years anyway; and with current rents and everything else, that's a lot to dump on someone. And if they're earning £30k per year, they'll just pay it off quicker, but still struggle.
If you're determined to help them out, then look for a good investment plan that'll reckon to mature in 18 years, and give you the £80k you need. Another option is to put about £38k in to stocks, and let it grow. But with the stock market going down at the minute, just save it in an isa for the next few years, then invest it.
About 20 years ago, my mum lent my niece the deposit on a house near her uni, and she rented it out to other students, covered her costs, and saw the house rise in value for her future, but you couldn't do that nowadays. I'm prepared to help out my daughter if she decides to go in a few years, but I know that if I give her the whole amount, she won't work as hard as she'll have to if she's contributing as well.
The futures not written yet, and all you can do is either prepare the best you can, or just wing it as circumstances change. Best of luck