Ewww. Grooved frets on a £40 guitar.
Yeah, your bloke was right. A refret or filing down of all the frets wouldn't be worth it on a low cost guitar. If you're still at in a few years, it might be something you could have a go at yourself.
So then, £250 for a decent guitar?
You happy to go second hand again? or would you prefer new?
Lefty/Righty?
Any preference (or hatred) of a particular shape? Do you want to be Angus Young/Slash/Hank Marvin?
Are you after an amp too? Rocksmith will fill in for an amp if needed.
Where in the country are you? Can you visit Guitarguitar/Andertons/PMT wave 250 notes at them and say "What ya got?". Spend an afternoon trying a few for size/weight?
Or take a look at any of the main sites (those 3 above are a good place to start), list all guitars and sort by price. There are a few very nice guitars for that price.
And don't be put off by your previous experience of Ibanez. IMO they make some very nice guitars. Not sure what your previous owner was doing with that one. Playing hammer-ons with an actual hammer?