Having used both Epson and HP 24" and 44" for commercial printing in my print & framing shop, I would keep well clear of Epson as they just waste so much ink, the HP on the other hand is fantastic in 3 years of heavy use ( in my printing & framing shop ) its never had a blocked nozzle or had any ink related issues, it also uses about 1/3rd of the ink the epson uses.
If your looking at buying an A2 printer, I would look at buying an A1 printer, this opens up a whole extra capabilities, as on A2 you cannot print an A2 canvas as you dont have the extra capacity to print the 4" wrap on each side. You will also find that your printer will require less maintenance than consumer products as they are designed to handle the extra capacity.
I only run OEM ink in my printer, I buy it from the USA in full sets at about 1/4 the cost of the UK. At that price i doesnt warrant the use of third party ink, but if i was looking for a UK 3rd party ink supplier I would look at
http://advancedinkjetsystems.com/ a friend of mine has been using them for a few years with no issues.
Oh yes i use a HP Z3200 44" printer with a built in i1 spectrometer and print using Shiraz Rip.
If i can answer any questions feel free to ask.
By the way this is my opinion based on printing photographic exhibition, fine art prints and canvas prints for approx 10 years commercially.