New house? What a poor install and poor boiler. She’s increased the Central Heating pressure. Thinking it would boost the HW?
The blue handle above the white pipe needs opening fully.
Someone thought about the install then. It's not right and your OCD may get a little more, because basically it's hanging on by 2 o rings. It looks a mess, plus you've damned it by taking it out like you have.
So you want a stylish radiator and want to bodge the fittings? Drain down, remove all old valves. Measure for your new stylish radiator, then decide and plan your next move. Cut and re-pipe or bodge it with compression fittings, or tail extensions. I'm sure your local DIY store can help.