What benefits would I receive if my new working partner moved in?

this is not the social services and it's impossible to estimate we do not have their information as every

case is different so there can't be a comparison you have to find out from them

You can't claim ESA if you're not sick and can only claim ESA if you're sick and have a partner if your partner works under 24 hours pw otherwise you lose it completely. Even if he works under 24hrs pw because it's a new claim paid at assessment rate his earnings would be far too high as he can afford to support your living expenses on his income. So no JSA or ESA I'm afraid.

When he moves in you're probably find you are eligible for Working Tax Credits which will be up to £70pw but that is the only additional help you will be eligible for I'm afraid. WTC are paid to top up low wages so when you close your Tax Credits Claim and put in a joint one they'll calculate whether you need WTC as well.

You will keep most of your Housing Benefit, all your Child Tax Credits and Child Benefit but your IS will obviously stop.

He should not move in with you. Your children should not be put in the position of having a boyfriend living in the family. It's all about what's best for your children and you should already know that.

If he is only making 204 per week, you will have to pay for part of his upkeep. That's just stupid and selfish to do that because any money you spend because of him being there is money that should be spent on your children.

Depending on what he earns, however you might be entitled to Working Tax credits. There can even be a disability element in there for yourself. I might follow anyway as you on no account know, you could acquire whatever. Your incapacity wont be affected so dont fear about that. Just right good fortune to your new condominium.

Really the only benefit is you getting to see him more. A couple isn't a real couple until they live together

Your best bet would be to try a website that calculates your entitlement. Google them, the address has Directgov at the start of it. They should give you a clear idea.