Hough 65C hydraulic relief spring

I have been having trouble with the hydraulic system on my loader. It has been slow to lift and dump and makes a squealing noise while raising boom.
I replaced the main pump, changed filters and oil but no change.
I then started to pull the main control valve apart and found 2 springs broken. 1 in a relief valve.
I have looked high and low for a replacement spring but have not had any luck. Part number is 208941H1
Any help is very much appreciated.

Hough 65C hydraulic relief spring