Now don't see the point of throwing good money after bad
We not financially strapped but just see this millstone getting heavier and heavier.... Am I being overly gloomy !
Yes you are, where is the financial burden? If you don't like and cannot cope with being a landlord then that is another issue.
There is no need for you to overpay your mortgage anymore. You should save instead. There is no need to overpay the investment as that is not in negative equity, is giving some kind of return, you will eventually owe it so long term what is the issue? Rents go up and down, as do property values, that is why it is a long term plan.
You live in a lovely home that all of you are happy with. You both have a good salary, for goodness sake how lucky are you? Also you have an investment property, can afford to subsidise that investment, and even if it went pear shaped you owe little or nothing on your home and the investment will just about clear itself.
Are you looking too closely at the paper losses, plus the 80K invested and gone and the long stretch of 18 years?
Maybe instead of overpaying you should spend some money on a nice family holiday or car. Think about all the positives, you don't seem to have any money worries that I can see only one's that you are looking for. Everybody including myself can go doom and gloom and say why didn't I sell in the biggest bubble Ireland ever had but hey we're still here, still working and getting on with it.
Don't be making plans to give property to your kids, make plans to have enough for your retirement, if you educate them they should be able to make their own way in life, and if there is anything over for them it's a bonus.