In fact the bulk of the Estate appears to be a mortgaged property.
I say this because the Probate shows that whilst the Gross value of the Estate is £325,000 the net Estate is £37,000.
This property is now held on a Discretionary Trust which can be used for the benefit of any or all of his children or grandchildren in whatever way his Trustees think fit.
This was almost certainly designed to protect the housing needs of the younger children although of course that is an assumption on my part
Whilst it is bad practise for the solicitors (who are also executors) not to have contacted to your children, not to have provided copies of the annual Trust accounts it is not fraud.
The starting point is to write a formal letter to the Senior partner at the firm pointing out that since they are also named as Executors and Trustees then the firm is under a duty to carry out that role properly - and that includes providing copies of the Estate Accounts and the annual Trust accounts; plus an indication of the basis on which the funds are being allocated
Some further information here
I hope that this is of assistance - please ask if you need further details