After suggestions for the following.
Where to source roller rockers for the 3 litre Essex. Yella Terra seem to have a couple of variations, 1.5 and 1.55 ratio. Studs are screw in.
Where to go for cam grinding, who do you trust.

I think roller rockers are the same as for small block chev, so that would give you more options.

Be careful with rollers as it used to be thought that holden 6 and SBC one fitted.  You need to ensure that the roller tip contacts the entire valve stem, not falls off one edge.  A friend had to get Yella Terra to relocate the roller tip on the Chev rockers to ensure this.  Ring Yella Terra and check before you buy.  You can get ones to suit press in studs but it kind of defeats the purpose.  Go the whole hog and get screw in studs.  ALso check the rocker ratio that it is the same as stock ( IIRC its 1.5???) if you get a different ration ensure you tell your cam grinder as he will need to factor it in
 
Cam grinds I use Clive Cams in Bayswater Vic.  He was the head guy at Wade cams before going off on his own.  And get your lifter re-faced at the same time.

gtv6capri
Be careful with rollers as it used to be thought that holden 6 and SBC one fitted.  You need to ensure that the roller tip contacts the entire valve stem, not falls off one edge.  A friend had to get Yella Terra to relocate the roller tip on the Chev rockers to ensure this.  Ring Yella Terra and check before you buy.  You can get ones to suit press in studs but it kind of defeats the purpose.  Go the whole hog and get screw in studs.  ALso check the rocker ratio that it is the same as stock ( IIRC its 1.5???) if you get a different ration ensure you tell your cam grinder as he will need to factor it in
 
Cam grinds I use Clive Cams in Bayswater Vic.  He was the head guy at Wade cams before going off on his own.  And get your lifter re-faced at the same time.

 
I believe standard is 1.5 ratio. Yella Terra are the only ones I have found with correct roller location. Not sure about the 1.5 ratio as they are diecast. 1.55 are extruded aluminium.
 
I have new steel lifters.
 
I was going to talk to Waggott in Alstonville about the cam, will try Clive cams as well.

I got the 152-A cam from Kelford cams.  They say its original specs but it doesn't match the specs in my book...but its awesome.  Nice idle and kicks in when you want it do.