Parking of Large Van on Shared Driveway

Tenancy Types and Management

Good morning
I would appreciate some advice as to how to deal with a situation I have at a property I let out.
The tenants arrived in July 2019. The house has a shared driveway and parking area with two adjacent houses. As tenants they are fine, the rent is paid regularly etc. However, it turned out the man is a DPD parcel delivery guy and parks his large van at home. Whilst he says he told the Agents at the outset that he had a %E2%80%9Cvan%E2%80%9D it was not disclosed that it was a very large vehicle which in reality, it too large for the space and initially it caused inconvenience to one of the neighbours in terms of ease of access to and from her own parking space. The matter seemed to subside mainly due to COVID but I have now received a further strong email of complaint from this neighbour. (The other neighbour has not commented because, I suspect, there are issues with her regarding their derelict vehicle which has been in the parking area for about 10 years.)
There is the usual clause in the AST regarding noise, disturbance & nuisance etc to neighbours as well as a requirement to observe the terms of the headlease ( a copy of which I do not believe was passed to the tenant at the time). The headlease also contains the usual clause about nuisance, annoyance as well as a prohibition of parking a commercial vehicle on the premises.
On the one hand I don%E2%80%99t want my tenants to be the cause of annoyance to neighbours but on the other hand, I am not sure if I should be getting involved.
Any advice you can give would be appreciated, thank you.