On a driveway use a long extension cable. Also fit a comfort connector for the Ctek, terminating at the grille area if connecting to the front or just inside the boot, then its a ten second job connecting up. Have this on all my cars as they may sit for days or longer. First time start even if Sorned for 6 months over winter ie S63
My 220/8 , when it was my dad’s car , could sit in the garage for months at a time , no need for maintenance charger as there were no electronics to drain the battery , and it would always start on the first compression . Most older cars were like that .
When I disposed of the W140 there was a nearly new battery in it , as I was giving the car away , I put the old battery back in and kept the new 130Ah Varta I’d bought . It now sits in my kitchen on a maintenance charger and handy to use to jump start any car that needs it . Not my W124 , to which I fitted a new Varta shortly after getting it , simply because the existing battery was of unknown history , even though it appeared to start the car OK .
Oh , my maintenance chargers are the £10 ones you get from the centre aisle of Aldi/Lidl a couple of times a year ; I’ve used them to keep several SORN or just less often used vehicles charge up , and they work great with settings for 6V or 12V , cars , motorcycles , cold weather and recovery of flat batteries. Of course more expensive alternatives are available , and I believe they work just as well .
For the OP , a solar charger placed in the front or back window , whichever gets more sunlight , can provide a trickle charge to keep a battery topped up if being left for a while . I gave one to my daughter since she used to cover 20 or 30 miles between MOTs , and it stopped me needing to go out periodically to jump start her .