It will be much better for baby if DH takes over the nights for the week. Or at least the first 3 or 4 nights. But if that's not possible you can do it, it will just be harder on your emotions because of night weaning.
Firstly and most importantly - your baby WILL cry. A lot. Try to reframe that crying. Baby's only way of communicating is through cries and baby is basically saying "I'm tired. I'm so tired Mummy/Daddy, please help me sleep". And that is exactly what you're doing. So you're not leaving him confused and distressed. You are teaching him. And sometimes learning new stuff is hard.
So don't take the crying in itself as a sign that baby cannot cope with what is happening, or that what you are doing isn't working. Accept that crying is going to happen, baby is just communicating with you. Stay caring, stay compassionate - it's really important not to get frustrated or angry and that's why reframing the crying is important. You understand that baby is tired and you understand that baby cannot get to sleep so is frustrated. You care and have empathy for your baby not being able to sleep and you are helping him and being compassionate of the fact that he's upset....
But (big but)... you do know best. You know that by teaching him to sleep independently his sleep will improve. So while you care that he is upset and frustrated, you also know you must carry on, be consistent and help him to learn. Because you understand the complexities of life that he doesn't. So you are taking this decision for him, because you are the parent and you know best.
That said, the practicalities...
when we put him to sleep would you say it’s still ok to pat his bum, rub his back as usual or should he be going to sleep with one of us just sat with him?
And in the night - just settling him the cot or pick him up and give him a cuddle?
As much in-cot comfort as is needed.
Always the same. No different at night, at bedtime, at naptime.
Gradual Withdrawal is like a 'ladder' of comfort given. You start off offering tons of comfort, and you do it right through until fully asleep. Then over time you reduce the amount of comfort needed very gradually.
Your first couple of nights will be hideous, be prepared for that. Seperate feeding and sleeping completely. For example feed before his bathtime, then into bath, into night clothes, into bed fully awake. Same at naptime in the daytime - feed when he wakes up not when he goes to sleep.
If he's pulling to standing, can he get from standing to sitting to lying down unaided too? (they usually can, if asked). If possible, put him in the cot standing up, tap mattress and tell him to lie down. In a "Simon Says" type way, babies love following instructions and getting praise. Practice this in the daytime if he doesn't have it sorted yet.
Mobile babies are like spaniel puppies - they won't stop being moving around unless you give them no choice and make them. So you may need to help him still his arms if he's flaying around in temper. For example hold his hands to keep him arms still. If he's similarly slamming his legs around, place your palm on his legs to still them. It largely depends what he's doing when lying in the cot. You want to help him keep still, but in a compassionate, loving way that you're helping him. In order to calm to go to sleep his body needs to still and relax.
So lie him down and accept that you (or DH) will be bending down into the cot for the next few hours. Give him as much comforting as you can in there. Patting, shushing, rub his back, tickle his cheeks, look into his eyes, have your face close to his if you can. All the comfort you can give. He's going to cry, just keep going - you're not leaving him, you're there with him all the way through and helping him learn even though it's hard.
Just keep going. Eventually (and it may take a long time) he will get there. As he does start relaxing, keep the comforting going. Gradually and slowly still and movement in the 10 or so minutes after going into a deep sleep. Then very carefully remove yourself and leave him to sleep.
Do the same for every wake up. I know, it will be very hard the first couple of nights.
So there might be times its unavoidable that he needs picking up. Screaming gives baby wind, which is painful, and this is a common reason to need to get baby out of the cot. That's OK, don't worry about seeing to your baby's needs, as long as you stay focused on independant sleep. So it's OK to periodically pick baby up, have him upright on your shoulder and maybe calm him slightly and see if he will wind. But don't do this routinely, only if it's absolutely needed. Also, I would highly recommend only DH picks him up, the issue of breastfeeding is not there with DH. Then put baby down still fully awake to carry on.
Gradual Withdrawal
None of this has explained to you how to actually progress to independent sleep. That's just because I don't want to overwhelm you.
As mentioned in an earlier post - your priority form now really needs to be night weaning. Just do anything and everything you need to do to night wean and not feed to sleep so that is your focus. Ideally in-cot settling only, that will make sleep training easier going forward. but if you absolutely can't then your DH could rock/cuddle to sleep for now. You can still do GW from rocking to sleep, it just takes longer. Point is, don't feed.
You start the process of gradually withdrawing towards independent sleep once in-cot settling is established. So first you need to establish that.