There are two issues.
Firstly, you should be relieved to hear that your parents would not be liable to UK IHT on any assets other than those sited in the UK. Furthermore, they would each have a nil rate band for UK IHT purposes totalling Â£255,000 in the year ending 5 April 2004 (Â£250,000 in the year ending 5 April 2003).
Secondly, obtaining probate in the UK in respect of a single asset such as cash in a deposit account is relatively simple. I refer you to the Probate Office see link:
You almost certainly do not require a lawyer, although you may need to swear papers before a Commissioner of Oaths.
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