The Joie ones are a good option.
Graco Extend R129 is also similar. The only thing to note with this and the Joie Steadi is that the top headrest height is fairly short, so your LO might not get all the way to age 4 in it unless they are small for their age. If that is a problem for you, it might be worth looking at Graco Slimfit R129 or Joie Every Stage R129, these are longer lasting, although they are a bit heavier and bulkier.
There is also a Halfords own brand seat called Halfords Impala which is rear facing up to 105cm / 18kg and belt fitted and is also light which might be worth comparing with the Joie/Graco seats.
IME though as a non driver, these seats are really too bulky to be carrying around with you for the day. They don't work well for that. they tend to be fine if you're getting a lift with someone and dropped off home at the end of the day, but they are not good for taxis unless you can store the seat where you are going (e.g. a birthday party).
My children are older and growing out of this age now, but if I was in this situation with a younger child, I would probably consider the folding seats which fit using isofix and top tether - Cosatto On The Go, or Kinderkraft Fix2Go. (Maxi Cosi Nomad XL is a more recognised brand, but I can not see any significant difference between this model and the cheaper ones in this case.) The only issue is that they are only forward facing, which isn't ideal. But the trade off is that they fold down much smaller which means you can fit them into a carry bag, possibly even under a buggy if you have a very large, accessible basket. The combination of 5 point harness fixed with isofix and top tether is a very good one as forward facing goes. No forward facing seat can compare with rear facing, and I don't expect the side impact protection on these to be great, but they are definitely better than nothing e.g. for taxis and I think they are likely to be better than older, seatbelt fitted folding type seats.
If money is no object, then Tinyseats 2 might be worth a look as it does allow rear facing up to 125cm and then converts to a high back booster. It fits using isofix and folds up, but it's not quite as light or small as the forward facing models, and it's over 4x the price.