I am going to guess that you have paving slabs on a firm base and they do not wobble.
Get a Pointing Gun and follow the manufacturer's instructions.
Not much chance of readimix. You will only need small amounts so I would mix it in a bucket. A quarter bucketful at a time. Use a bottle or measuring jug for the water because you will add too much. A garden trowel is quite good for mixing in a bucket as it will get into the corners. Wash the tool and bucket with a hose and put the remains on your compost heap, hosed around. Never put mix down a drain.
pigletjohn, have you ever heard of Rompox Romex? I thought about this as one £45 tub is meant to do a largeish patio, but you're meant to literally dump the tub on the cleaned patio and then sweep it over the lot... It sounds top easy!!.... Any thoughts?
sweeping mix to and fro so it falls into the joints is the traditional method, but I think the gun will be better.
Their product appears to have an air-setting adhesive in the mix rather than ordinary cement, which might account for the high price. It appears to be a wet mix which is more likely to stain the tops of the slabs.
Good point re too heavy to lift! Thanks for the advice
I'm trying to put off doing our patio til we have time to properly clear and clean it. The Romex stuff is advertised as "coating" the whole patio surface which then "weathers with time", so clearly it does stain so they are trying to market this as a selling point!!! Well, points for effort anyway.
if you can lay your hands on a power jetwasher, it will get the slab clean (will take off the top skin from the concrete) and if you squirt it into the joints it will wash out the grouting (this is why it is usually not recommended) ready for you to immediately re-grout.
makers instructions will tell you. I expect it will be something like 4 of sharp sand to 1 of cement and a little water, but see what they say. They might recommend an additive to improve flow or frost resistance.