Models with foreign key fails in sqlite (with foreign keys enabled)

This is driving me a little crazy. I can easily work round it but it seems a shame to change the code to suit tests with SQlite.

I migrate my 'crop_requests' table.

Schema::create('crop_requests', function (Blueprint $table) {
            $table->increments('id');
            $table->integer('user_id');
            $table->integer('business_id');
            $table->string('request_reference');
 	    $table->foreignId('supplier_business_id')->references('id')->on('businesses');
            $table->string('crop_reference')->nullable();
            $table->integer('supplier_member_reference')->nullable();
            $table->integer('requested_crop_reference')->nullable();
            $table->integer('requested_crop_id')->nullable();
            $table->integer('user_follows_croplink_id')->nullable();
            $table->string('status')->nullable();
            $table->timestamp('read')->nullable();
            $table->timestamps();
        });

I then migrate my 'businesses table'.

From my Business model

public function incomingCropRequests()
{
        return $this->hasMany(CropRequest::class, 'supplier_business_id');
}

When I run this with mysql it is fine but SQlite tests returns empty

$cropRequests = $this->loggedInBusiness->incomingCropRequests;

If I change it to the following it runs fine on both databases.

$cropRequests = CropRequest::where('supplier_business_id', \Auth::user()->business->id)->get();

The models are in the databases okay each time. Foreign keys are enabled.

As per usual I'm probably missing something blindingly obvious but can't spot it at the moment!

On Laravel 7.30.1 , SQLite 3.19.3.