What do I need to do with land registry before selling inherited part share in house

My sister and I have inherited a 50% share of my Dads former home as he passed away.

The house was registered as joint tenants with his long term partner, but he had agreed with her that his half would pass to me and my sister when he died.

She therefore completed a deed of variation to his will with a solicitor with splits the property upon his death and my sister and I therefore own half of the house.

His partner wishes to sell the house and move to something smaller and at this point she will release our share of the house.

So that the house sale can be completed without any complication, what do I need to do to show that we are now partial owners with the land registry?

Any help or advice would be greatly appreciated.

many thanks 
Helen

Helen - it reads as if there's nothing to do re the land register as the partner is going to sell and then divide the proceeds as appropriate.
The legal ownership, which is what we register, passed to her on your late Father's death. And as they were registered as joint tenants she can now transfer (sell) it as appropriate.
Your and your sister's share is in the beneficial ownership, so the £s and pence realised when the property is converted into money for example when it's sold. 
So as mentioned if that's how things are then she can sell, receive the purchase monies and then divide them as appropriate. 
The only thing the buyer will need is a certified copy of your late Dad's death certificate to confirm his passing unless the register has been updated already re the death so it's in her sole name anyway.

Thank you Adam, I really appreciate your advice.  

I just wanted to check as the way the deed of variation was worded it implies the property should now be treated as tenants in common and that the joint tenancy was severed upon my father’s death.

Thank you again for taking the time to respond, this is all new to me and as the executor I just want to make sure I’m doing everything correctly.

Helen

Helen - understood and appreciated but the variation is I assume varying the will/trust itself. As such that doesn't change the legal ownership which we register.
Changing to tenants in common might warrant applying to update the register and to apply for a form A restriction as it's known. But as the property is being sold there's no need to as the will/trust/variation are all still in play legally and are linked to the value/share of/purchase monies so can be resolved once the property has been turned into the £s and pence I mentioned.
Tenants in common can still be so even without changing the land register
The complexities of the legal and beneficial ownerships are such that very few would naturally understand them or view it as 'simple'. Dealing with the loss can be stressful enough and the wills/trust etc are often where the complexities lie.
The legal ownership which we register is often the simplest part of it all but it reads as if you have a good grasp of what's to be checked/understood.
The key, in my experience, is that the law largely relies on everyone understanding the wills/wishes of the deceased and working together, with the executor, as appropriate. It reads as if you are all on the same page so to speak and realise that once sold then the £s and pence can be apportioned accordingly.
The only extra point to make is that in this case it is his partner who is responsible for that as the legal owner of the property in any sale so she will take receipt of the monies and then disperse them. Your role as executor is responsible for dealing with his estate which does not include the legal ownership of the property but does carry a responsibility of ensuring that his beneficial share is distributed as and when realised after the sale. And as you are working with his partner (and your sister) to that end it reads as if you are doing everything correctly. 
If you all continue to work to the same end then I'm sure it will play out as your late Father and his partner both planned and wished for. If you have any further doubts then I would suggest seeking legal advice for that extra reassurance if needed

Thank you, I am extremely grateful for your reassurance on this matter and your explanation is very informative and helpful.

As you say it is difficult and stressful dealing with these matters, so your help has been very valuable.

Kindest regards
Helen