intereting issue, not suggesting you con your energy company as no doubt they will catch on but are you sure this is your import meter? I have a meter installed bt the company who done the solar, they told me it would act as an export meter but it does not as it counts electric that goes to the house so is basically a random number, it does not matter for me as my SMETS2 meter does the export as it should.Yes I watched the installer program the inverter & he force charged the batteries from the mains to make sure everything worked. Therefore I do know how to do it.
HOWEVER... on checking the FIT meter while charging I saw it had been fooled into thinking that the energy had come from the PV which of course would pay out to me. (when I showed him this he realised I was right, not something he had ever thought about. I reassured him that I would never do that... & haven't!)
Therefore I don't feel comfortable with force charging as I would be paid for something I haven't generated legally!
If your meter is going that wrong I would be interested in how it is wired, general rule of thumb is it goes fuse then meter then either a consumer unit or Henley blocks to split to two consumer units, with that in mind the meter would not be affected by any purchase other than see it as normal usage,
if you can use purchasing my opinion is solar, battery and time of use charging is the real game changer.