OK stop the press - I may have found one - Apramo All Stage. HOWEVER, it's expensive. Your car MUST be on their fitting list. It's a combo seat which is usually not the best (particularly as a booster). Apramo is a little known brand. I couldn't find much info about them, and the ADAC result for this seat is not good - the most detailed breakdown I can find is here: erfmission.com/adac-2019-apramo-all-stage/
Sorry, this probably just confuses things further. 
The rest of my post describes what I found before I saw this one :)
The in car safety centre won't fit any seat with a leg into a car with storage boxes regardless of what the manufacturer says. So you will be more restricted by their policy, even though they stock more seats.
Do you have isofix in the middle seat? That could work, some legs can be fitted over a hump, or a seatbelted 25kg seat in the middle seat. In car safety centre or another ERF specialist could advise here.
You might have to compromise on swivel or length of rear facing. I don't know that you'll get both, as all the swivel seats which RF to 18kg use a leg. (See above - but this is still rare). The maxi cosi ones (two FF only, two RF to 87cm - average 2y, but goes by height) are the only (well known brand) ones which don't use this. This seat is £275 on Kiddies' Kingdom, cheaper than MC/JL. There is also the (extortionate) Axissfix air, which is RF to and then FF with airbags, which apparently(?) reduce the risk of FF - might be worth a look.
Besafe izi twist may be worth a look. The legs are pulled out to a wider angle (more towards front of car) so may fit in front of storage box. It might also be long enough to go to the bottom. But again, it's not cheap. Besafe is a respected brand in the car seat world though. Cybex Sirona Z may also have a long leg - again pricey as a combo (maybe check other Cybex seats, as some of them are affordable, and GB Vaya, which is the same company). Britax does not allow this and Joie (and presumably Nuna) generally are too short to fit.
Looking at just 9kg at 15 months, your DD probably won't reach 13kg until just about her third birthday, so a combo 13kg RF / 18kg FF seat might be OK for her, if you're OK turning her at three. Unfortunately the two maxi cosi ones definitely go on height rather than weight. If she's on the same centile for height as she is for weight that only gets you to about 2.3. If she's on a higher centile for height, less than that. But if she's on the 9th she might get to about 2.6 and on the 2nd she might get to almost 3. You'd have to measure her and take a gamble on it. Personally, I'm OK with FF at 3, but I know not everyone is. If you look at the data from Sweden most children are turned at either 3.3 or 3.9, around half of their 3 year olds are forward facing, and they have very low death rates for children in cars. But obviously, rear facing is still safer for as long as possible.
So non swivel options:
Axkid move/minikid (ERF to 25kg) have long support legs which can fit to the bottom of a storage box, if your car manufacturer approves this. Not swivel, just RF. But fairly low sides so may be easier to get LO in without turning.
As mentioned above, Britax Two Way Elite or Diono Radian 5 brace on front seat, so can fit without a support leg. Not swivel, but RF to 25kg - also low sided.
Worth noting if you go for one of the 25kg seats she may be too little to fit the smallest harness position, if she's also shorter than average. 18 months might be a more realistic age. But if she is tall/average and slim then you might be OK to go into them already.
You could look at Joie seatbelt fitted seats - Every Stage, Stages etc. But these are even more annoying than a normal non swivel seat to use because the seatbelt covers the gap to put the child into.
If you want to fit a support leg to the bottom of the storage box, this must be approved in your car manual. It may be referred to as a "stay".
Hope this is helpful and not just more confusing.