The general formula is 2g of protein per Kg bodyweight.

How do you know, however is this is too much or too little?

It must be relative to how much stress you have put on the muscles, so you could end up with a surplus amount that I believe converts to fat (please correct me if I am wrong).

How do you know how much Protein your workout requires you to consume without it becoming a waste of time?

Depends on how you metabolize food in my opinion...
Then the demands of your work/sport etc...

A big factor is what your ancestor is (this isn't absolute but usually a big indicator)... if your background is northern European just think what they ate before stores and electricity and shipping foods from all over the world. Meat, seasonal veg and fruit etc yes seasonal (in the winter no one's picking oranges..

The trick is in part to see how you feel after eating and a couple hours after... and fine tune your personal fuel ratios (carbs/fat/protein)...

extra carbs is a bigger problem for most - carbs is just fuel... fat and protein are also building blocks and make up your whole body... extra carbs turns to fat in most people way easier than protein or even fat will...

I take Protein supplements though, and as I weigh 85kg I was consuming approx 170g of protein per day (supplement + food combined) going by the generally held formula.

Is it something like 70g max is the suggested consumption for the average male adult, so am I doing enough in the gym to warrant that extra 100g or is my gym work being completely undone by taking too much protein which turns to fat?

I can regulate the Carbs ok, its more the protein I am bothered about.

I tend to do a 1 hour session on the weights 3 times a week, 99% of the time 3 sets of 8 of whichever exercise, always with weights I am really having to work on the 7th and 8th rep, so I presume I am putting a fair bit of stress on the muscles over that hour?

I would look at metabolic typing to find out what ratio of carbs, fat and protein works for you. There are three main groups and after that its all about fine tuning for you.

Got the metabolic typing diet book and it was cool, made a few changes after reading it and has worked wonders. Needed to add a few things but its a cool book to have a read of and learn a bit of history as well.

Mordan - for most people it should work well, some cases might do best on a rotation diet (course you can still do that with Metabolic Typing) and some with food combining (again can do with Metabolic Typing).

Glad to hear its working for you.

There is more in depth tests you can do than are in the book.

A protein type might be a fast or slow oxidizer or might be sympathetic or parasympathetic dominant (or in between fast and slow, para or symp) with in protein type there are those 6 possibilities, all with different diet plans.
(same with carb type and mixed type)

But just getting the fuel ratios down goes a long way for many - did for me.

I'm guessing from your location and pics that you are a protein type?

Hey mate originally from Australia and back here again but spent many years in the UK. When you look at it though my ancestors were from Ireland so similair to scotland in the climate and foods that were available then.

Bread and the chemicals used in them are a massive downer for me, I can be asleep in 15 minutes after having bread, so I try to get my carbs from beans or tortillas and lavash bread.
yeah I'm a protein person, does my wifes head in as well as I have to have meat with everything.

lol she might find she does better that way too :)

The best I have ever felt in my life was when I wasn't eating any grains at all, maybe rice here and there or sometimes some oats but for months went with none at all - felt amazing. Got carbs from seasonal fruit and veg - root veg if needed more or out of season fruit a bit.

Bread goes straight to my head...

Think about it, we come from hunter gatherers. We followed the meat we didn't follow the grains lol actually farming is when people settled down, had something to protect and really lead to wars... not like there were fields and fields of grains in nature and old school, the small amount they had, fermented them mostly...