In relation to the barrister, I am not sure whether this would be in your interest given that she is not regulated by a professional body. If you want a barrister to deal with this instead of a solicitor you should consider finding a barrister who accepts "direct access" work.
In relation to the finances specifically, the amount he is offering you is not an equitable settlement. There is £335,000 equity in the property. He is offering your £100,000 which is less than a third of this. There is no disclosure of other assets, savings or investments and the total asset pot could be higher than this. It also appears that you are not sure of what his pension value is - and this will be relevant given your long marriage and both your ages as you would be entitled to claim from this.
Furthermore, given your disparity in income, you would be entitled to either pursue spousal maintenance to meet the shortfall between your reasonable needs and your income, or to claim a greater share of the assets by way of capitalising maintenance as a lump sum. I would therefore suggest you seriously consider his offer as it does not appear to be in your interest.
As part of negotiations or mediation you will both need to provide each other with full and frank financial and income disclosure, as well as disclosure of your reasonable needs. The Court's starting point is a 50-50 split of all matrimonial assets and ensuring that both your needs are met in relation to both assets and income. For your information the criteria considered by the court in these matters is:
1. The income, earning capacity, property and other financial resources which each of the parties to the marriage has or is likely to have in the foreseeable future, including in the case of earning capacity any increase in that capacity which it would in the opinion of the court be reasonable to expect a party to the marriage to take steps to acquire;
2. The financial needs, obligations and responsibilities which each of the parties to the marriage has or is likely to have in the foreseeable future;
3. The standard of living enjoyed by the family before the breakdown of the marriage;
4. The age of each party to the marriage and the duration of the marriage;
5. Any physical or mental disability of either of the parties to the marriage;
6. The contributions which each of the parties has made or is likely in the foreseeable future to make to the welfare of the family, including any contribution by looking after the home or caring for the family;
7. The conduct of each of the parties, if that conduct is such that it would in the opinion of the court be inequitable to disregard it;
8. In the case of proceedings for divorce or nullity of marriage, the value to each of the parties to the marriage of any benefit which, by reason of the dissolution or annulment of the marriage, that party will lose the chance of acquiring.
If you have any further questions regarding this please let me know. In the meantime if you found this information helpful please provide a positive rating using the stars at the top of this page. I will not be credited for answering your question without a positive rating. Thank you