[greenhead]

I have a row of Autumn Bliss raspberry they have been in about 3 years but last year the crop was poor (small berries) I think I need to top dress with something?  What should I use?  Well rotted horse manure or compost or perhaps BFB.  Advise please.

[stompy]

I would apply BFB, then mulch overt the top with manure.

[Hobnails]

I make a slurry with neat horse dung ( no straw etc.) and mulch them with that.

[stompy]

I make a slurry with neat horse dung ( no straw etc.) and mulch them with that.

Thats more a feed than a mulch though.
The mulch of manure 3 to 4 inch thick will supress the weeds as well as keep in moisture.

[greenhead]

Thanks  stompy and Hobnails will carry out your recommendations this w/end.

[Yorkie]

Make sure that the mulch doesn't actually touch the stems though

[totalnovice]

am planning on using grass cuttings, didn't know not to let it touch the stems so thanks for the tip Yorkie.