Equity release is a really poor deal. You'd be better to downsize and free up some capital and enjoy it. Your kids will still have an asset to inherit.
If things are a bit tight now, it's going to get much worse ; in a few years time you'll be struggling to heat a large property.Even if you have always done all your own decorating/maintenance/gardening, in a few years time that will be much harder and you'll need to pay someone to do it.
When one of you becomes frail then dies, the other will struggle to manage a big house and be rattling around. Far better to have a home that's appropriate to your age and needs ( I'd recommend, large downstairs bath/walk in shower, a downstairs bedroom, walk in shower; consider access to busroutes /shops facilities if you can no longer drive. 2 beds, one for guests, or one each if one becomes disabled). Cheaper bills. Get rid of a lot of unwanted clutter
Now is the time to downsize, while you have the energy to househunt, pack, move, settle in a new place. Don't wait until one of you is ill /less mobile,. I've seen older friends very rapidly lose most mobility and too late then for the stress of stairs, househunting. etc.