I've just returned from Owen Springs, Rotherham.
Prices for springs from 1 1/2" x 3/16" (it's all imperial size steel), 570mm span, 80mm camber -
EACH -unbushed (3/4" eye) £68, bushed for 1/2" £88 - based on 2 springs (one pair).
And one for the committee to consider -
Based on 20 springs (10 pair) unbushed £51, bushed £61.60 each
plus vat and carriage if needed.
It appears that material costs have risen sharply over the past 12 months in addition to processing cost (gas for heat treatment?).
I shall get a current price from Jones Springs before placing an order.