2011 iMac potential GPU failure, worth replacing?

Hi,

I bought a mid 2011 27-inch imac last year for about £400, did it up replaced the ram changed the drives out - was perfectly good for everything I needed it to do, until recently when it suffered what I assume was a GPU failure (very characteristic of this model)

the screen would occasionally flash and distort, sometimes I'd get lines on the screen, and then it crashed, and now it won't boot (the loading bar gets about halfway up, freezes, and then i get the grey screen of death).

I'm just wondering whether people think it's worth salvaging. Obviously the boat has long sailed on the apple replacement program for GPUs on this model, and I bought it secondhand anyway so have no "applecare" or insurance. I've noticed people sell the replacement cards online, but they're about £200 (from what i've found at the moment) from china, and while I don't mind fiddling around in one of these machines, getting to the motherboard is not an easy process.

Considering all this, especially that it's £200 for a 7-year old part, I don't know if I'm better off spending the £200-250 and hopefully bringing back a great iMac to full working order, or if I should strip out my drives and let it go to the apple graveyard and invest the £200 elsewhere.

While it seems like a shame to just bin it off, especially after such a hefty investment in it, I'm slightly worried about fixing it only for another issue to present itself a few months down the line, and my £200 fix to have been another waste of money. Especially considering it's an old and outdated machine.