This one? It looks to be exactly the same design, with just slightly differently shaped slots cut out of the uprights, which don't look like they'd make a positive difference to the strength, and the shelves look to be chipboard rather than MDF, so that's at least one aspect that's worse on the Aldi. The thickness of all the steel rails looks the same, and this is the only variable that would make a difference to its sturdiness and longevity. I'm not saying you're definitely wrong, but do give some more details about what makes the Aldi better, especially since it's about 30% more expensive.

Aldi in Ewell still has them. Seen it couple of days ago. I got another shelfing 50kg per shelf for 13.00. About same dimentions but made of plastic.

It does LOOK exactly the same, although JTF specify a vague "Strong metal framing"! It surely has to be steel, after all, there aren't really any metals cheaper than steel that will support even vaguely decent weight at that sort of thick(thin)ness, but it would still be good to confirm, so maybe you could take a magnet to it and let me know?
Also, it LOOKS silvery, but again, that may easily just be a paint finish, and a galvanised finish is MUCH more durable and way more rust-resistant than any paint finish out there, even powder coating (which that won't be, as it's not a cheap process, and these are distinctly low budget) so can you tell if your IS galvanised or not? If it is NOT, then the galvanisation is certainly worth more than the £2 difference.

That sends you to B&Q not Homebase. I love a good shelf.

Well, obviously, but there's nothing stopping any of you from putting on a couple of layers of varnish on each of them, which I'd consider essential for this sort of shelving unit - it will also help with cleaning the inevitable build-up of dust over time, as well as wiping off any possible spillages. The good thing is that the weather has just become perfect for this kind of job (which should to be done outside because of the need for ventilation) since ambient temp has to be above 15° C and obviously dry, plus it's a perfect Sunday afternoon kind of job! Pay closer attention to the edges of the boards, Ronseal PU varnish works great (£6.15 a tin for the smaller 250ml, which may be enough for the 5 shelves, though I can't guarantee it, what with two layers on both sides; it might need the bigger 750ml, and then you save a bit per ml and you'll have a fair bit left over for other jobs) For a halfway size of 500ml, there's this Ronseal Yacht varnish @ £11.69, which has the added benefit of being an outside formulation.