Quite often after a settlement or tribunal award the respondent will send only part of the amount due.
Normally, although not always, they will offer some sort of excuse for this. These range from the really rather plausible through the quite possible to the downright unlikely. Depending on the quality of the excuse, you may want to consider starting to enforce the award.
But whatever else you do, pocket what is actually on the table. If it is a cheque, pay it in. If it is cash or a bank transfer there is no need to keep it separate to other money or avoid spending it.
People are often worried about this. They fear that, by paying in a cheque for half the amount, they may lose their entitlement to the other half. If the respondent is trying to sell them on payment by instalments they want to be sure that they are not seen as accepting that.
This is just not how things work. As a practical matter, it may be sensible to write a letter making your position clear, since it may prevent the respondent getting confused. But as a matter of law taking part of what you are owed does not change your entitlement to the rest of the money, or commit you to anything that the respondent is proposing.