Gas water heater (dux prodigy) noisy one way valve

[zillah]

Dear folks

I have got Gas storage water heater (dux prodigy) with noisy one way valve ,,,,,,,my case i have :

one way valve (the one with arrow) plus T head Stop Cock M/M.

I called two plumbers they quoted $400-$450 to replace it I feel (i could be wrong) over priced ?

https://directwholesale.com.au/products/avg-non-return-isolating-valves-f-x-f-15mm-1-2-nribv-15f/

My question would Duo valve a one way valve and isolation valve from AVG

suffice the noisy one way valve (the one with arrow) and T head Stop Cock M/M ??

Thx