Rasps and mushroom compost mulch

I'm not sure how much difference it would make. I have heavy clay on top of chalk and I gave up doing soil tests years ago. When I had them done I got results showing Ph of 7.2-7.5. I have never done anything to alter that and my raspberries have been growing happily and producing loads of fruit for 15 years. I do grow blueberries in pots of ericaceous compost but everything else is sown or planted in the soil and I'm happy with the product. I'm not aware of anything that would grow any better if I set about altering the Ph value which is not a simple job(IMO).

That's good news. While clay soils can be slightly acidic, mine is alluvial silt and, as far as I know, is about neutral pH. I will put on a goodly amount then wath the leaves to see if they show signs of chlorosis. If they do, I will water some Sequestrine in.