Thank you everyone for your posts, I thought I'd update this thread with the latest, I've included that below the post answers...I have a solution!
In reply to your posts:
davidh202 - I don't think it's damaged, I have no way of knowing but the blockage hasn't shifted either way.
BrianWJH - we did leave it soaking overnight which unfortunately didn't help at all.
Paul2660 - thank you for your detailed reply, we tried a SSCL following your suggestions which didn't help at all, I have called Epson UK this morning and I've updated the thread below with the outcome.
Farmer - the blockage hasn't shifted, it got worse weirdly after doing the Windex trick and then has gone back to exactly where it was before, so it got worse, then better, but only back to the original blockage.
The update...I've rung Epson UK this morning and got through to a very helpful chap in large format tech support. They have an 0871 tech support number which is 10p per minute but if you ring 01952 607100 it puts you through to exactly the same place and is a standard geographical call.
He said it sounded like the print head was blocked but obviously couldn't say for definite. He gave me two options:
1.
Send an engineer out
Replace the part/s
90 day guarantee
Standard price of £1200 including VAT at 20%
2.
Send an engineer out
Replace the part/s
12 month warranty
Includes a maintenance service which I can redeem any time within the 12 month period for changing things like wiper blades etc.
£1500 including VAT at 20%.
I've gone for option 2, having the printer under full warranty for that amount of time including call out charges and replacement parts sounds like quite a good deal to me...well, it's still hellishly expensive but not as expensive as all the other prices I've been looking at!
So I'm now waiting for an engineer to call to arrange an appointment hopefully for tomorrow so fingers crossed they contact me later today!