You can apply to be your Father's administrator (as you are a beneficiary).
However, there are some set Forms you and the Executor will need to sign, and if you are not familiar with these, you are best to ask a local Wills Solicitor to draft them.
Basically, the Executor will need to sign a Form called a Deed of Renunciation. You may be able to download a copy from the internet for a small fee, if you can find one.
You will then need to apply to your local Probate Registry to be Administrator of the Estate. If a Solicitor was acting for you, he would prepare the necessary Oath which you will need to sign. If you want to do it yourself, provided you have the signed Deed of Renunciation, you can make an application yourself to the Probate Registry, and they will then send you the necessary Oath to swear.
I hope this assists and sets out the legal position.
Can I assist any further? If I have helped, please don't forget to rate my answer. Thanks Al