Not sure whether you could buy a bit of fuel and then together with the landing fee they could come to the £45 minimum charge.
Also, if I remember correctly there is a discount if you settle up there and then. I guess it saves them sending out an invoice and having to chase for their money.
I also believe they will halve the charges if you pre book a training slot. So you could book an ILS and landing for training. Buy a bit of fuel and walk away £45 lighter.
No one round here goes there anymore as its all yellow vests. Not all their fault really as the ramp has scheduled flights and they have to have security levels appropriate for this. GA with its toothpaste and bottles of wine gets treated the same. After all, you could just leave something airside for a commercial passenger to pick up.
ZA