The short answer is yes, the longer answer is...
In the United Kingdom there is no law forbidding recording calls (other countries will differ) and there are no laws mandating absolute consent, the regulation is significantly more complex and is based around the intent and purpose of the recording.
Assuming your use case for the recording the call is for EITHER ensuring the safeguarding of beneficiaries, volunteers and staff OR the training of staff and volunteers, then you can record the calls providing you adhere to the following:
Make reasonable efforts to inform all parties that calls maybe recorded and why – this could be as part of your volunteer or beneficiary onboarding.
Do not use the recordings for any other purpose than those stated above and do not share the recordings with any third parties.
Avoid discussions that could reveal information that can identify the individuals taking part, this would include full names, addresses or phone numbers.
Store the recording safely in a secure location. – such as with Together.ly – we’re ISO27001 certified
If you want to dig deeper on this topic then the specific pieces of legislation that influence this are the Regulation of Investigatory Powers Act 2000 (RIPA), the Investigatory Powers Act 2018 and the Data Protection Act 2018 (GDPR).