On the way home today, all was good but then I went to overtake a lorry, it felt weird there wasn't the usual power, hardly any pull

Then 2 minutes down the road it just cut out without warning, rolled to a stop and tried to start it again but nothing. All the electrics worked, turned the ignition and I heard all the usual whirring of pumps etc, but nothing from the engine

Matey from RAC turned up and I stuck it in 1st while he rocked it back and forth, it didn't move much and I could see the engine wobble when it went backwards.
He reckons it could be the bottom end seized

The top end was fine apparently

What would be recommended, get it fixed ie new bottom end or an entire engine swap (8v gti digi)?
I know a mechanic that can do stuff cheap for me, only charged £120 to fit the clutch.