Tax due on Savings Interest for Allotment Society

I'm the Treasurer of our Allotment Society and have recently opened a savings account linked to our business account with Lloyds Bank. We have £3k in the savings account and it will generate around £40 a year in interest. The capital in the account is almost entirely from a scheme we have for members to pay a "bond" when they join the society which they get back if they leave their plot in good condition when they resign, but which is forfeited if it's in poor condition at that point. The surplus from the bonds is used to help new members get a poor plot back into good condition and to provide site improvements otherwise. My query is whether there is a tax liability for the interest in the savings account and whether we need to register with HMRC to pay any tax due. https://www.gov.uk/hmrc-internal-manuals/company-taxation-manual/ctm40575 seems to imply we may need to pay tax on the interest.

Hi Peter Bradbury,
HMRC will require your organisation to register for Corporation tax and submit ian initial CT600 tax return.
But please also consider the guidance here:
Corporation Tax: trading and non-trading
Whilst the interest on your organsisations savings account is taxable this guidance will tell you the circumstances in which HMRC will consider your organisation as dormant.
If the criteria for dormancy have been met then please write to HMRC:
At Corporation Tax Services
HM Revenue and Customs  BX9 1AX
To change the status of your Corporation Tax record.
Thank you.