Hi Whizzpopper saw your request for help with steering and as we are not too far from you (near Worcester) and we have our own demo boat (6.2mtr 75DI Evinrude) fitted with hydraulic steering which you are more than welcome to come and see if you like. The boat tops 40knots and is a breeze to helm with the hydraulic fitted it really helps smooth and balance the torque not the cheapest option but probably the best end result.
An less expensive alternative would be to fit NFB (no feedback) mechanical steering this also removes the inbalance of conventional steering and offers a little "assistance" for about £1£170.00.
PS we also supply and fit steering if this is of any interest to you.
If you`ve got any other questions you can drop them to me at
steve@nautequipe.co.uk.
All the best,
Stevetheboat