Whilst cleaning the areas I spotted that the bolts are original Allen key - and they are tight!!
Gotta buy a socket type allen fitting as I dont trust keys not to snap under that force + I fear there may be some damage or total mutilation to the heads during removal

So as I am this this stage I want to change them for the spline type but can;t find a source.
Any recommendations (I have tried Brickworx and ebay but only find Allen type).
Also, can anyone confirm the size of the bolts please? M8 x 50 ?
cheers