EM6234 - Contract settlements: expected offer: means - unjustified claim
The guidance about contract settlements at EM6000+ only relates to direct tax. You must never include VAT or VAT penalties in a contract settlement.
If you are satisfied with the customer's ability to meet their liabilities by a standard cash offer, but are unable to obtain such an offer from them, you will have to proceed formally following the advice in EM5200+.