Seat Ibiza 6L: Remove Dashboard for Expansion Valve?

Hello,
I'm not really an expert in this area, but I would still appreciate some knowledgeable information.

According to the repair shop, the expansion valve (located on the wall between the engine and the interior) in my Seat Ibiza 6L 1.4 TDI (manufactured in 2006) is leaking, and green refrigerant is escaping. When the air conditioning is running, it makes a hissing sound from the vents inside the car, and it's not cooling as well.
According to the employee, it could be the seals, which would cost 5 euros plus 1 hour of labor.
It's also possible that the expansion valve is faulty, and if that's the case, the entire dashboard would need to be removed because it's only accessible from the inside. The workshop estimates the labor time to be difficult to determine, but it could be 7-8 hours.
Could that be possible? Can't it simply be replaced from the engine compartment?

Thank you for any clarification!

"Let's start by replacing those two O-rings and then check the system for leaks before filling it with nitrogen. I recently had a 2004 Passat in the shop, and it turned out the leak was only due to the O-rings."

Yes, that's the plan. However, the employee mentioned that it's more likely that the valve is faulty and needs to be replaced.

You can blame a lot of things... electric valves rarely leak, but the seals usually become hard over time... I worked in the vehicle/transport refrigeration industry for many years:

http://www.konvekta.de/busklima/produkte.html

http://www.carrier.com/truck-trailer/de/de/products/de-truck-trailer/truck/

http://www.frigoblock.com/de/produkte/ek-dk-reihe/ek-25-sl.html

Okay, then I'll be keeping my fingers crossed for you!