Seriously consider the 145 from clarke then, along with a regulator and rent free gas bottle you'll be hitting home at around the 300 mark if you've got a VAT free code.
you don't need anything bigger at home, it will burn a hole in 4mm plate with enough effort but can lay down a nice stringer on 20 gauge without any real issues. grab a pack of tips and a fluted shroud to make it a bit easier to see whats happening. oh and it comes with a free mask shaped object, the glass from which is perfect for using as a scraper, the rest is garbage.
a 5kg spool of flux core is around 30 quid (I appreiciate you maybe getting it free at first, but the stock isn't for life), that gets you a 15kg of mig wire with change, 3 times more welding, it quickly adds up to a bottle of gas.
I keep a roll of flux core in, just in case I'm middle of job and the gas runs out, I can swap over and keep going if I have to, but the weld quality suffers, it's like going from cutting butter to cutting cheese, both are easy but one is just so smooth, lol.
heres where I get my gas from.
https://www.gas-uk.co.uk/rent-free-gas- ... elding-gas
it's rent free but there is a deposit on the bottle of 80 quid and 11 quid delivery, so your looking at more like 130 quid for a 10 litre bottle (i get 20 litres at a time at the moment)
other option, if there is one in your area is hobbyweld, who do a bottle with built in regulator, but don't deliver.
hope that helps.
If he wants to learn to weld, find an old buzzbox MMA and teach him to hold an arc first, he'll be such a better welder for it.