Car needs major engine repairs after 5 weeks (England)

Context:

I recently bought a 2012 Kia CEED from a dealership near Birmingham (21/02/26), and was sold to me with no noises or reported problems - the engine was even advertised as "in perfect condition"!

However, over the weekend (28/03/26 - 29/03/26) I noticed a strange rattle while in motion. Didn't think much of it as there was no warning lights and no difference in driving but decided to get it checked out anyway. When I took it to a local garage they didn't even want to test drive it because they suspect a bearing rod failure from the noise alone. According to them (although they admitted they don't deal with engine faults) that means I'd need to rebuild the engine. Said local garage also said they suspect an oil pump failure had happened in the past, and that had degraded the rod to the point it's now failing (they suspected they had filled the car with oil prior to sale).

I'm getting an official diagnostic letter on Tuesday (07/04/2026) from a Kia specialist, and then immediately contacting the dealership to make a case for them to pay it under the Consumer Rights Act. It's not as described (engine can't be in perfect condition if it needs this major of a repair so soon) and it's not fit for purpose (according to the same garage it's a big risk for me to drive it anywhere as it could just break down)!

I do not have the savings (especially so quickly after buying the vehicle) to afford a potential 7k repair - even making a claim through my AA warranty only reduces it by a grand! I'm visiting family the end of this month (22/04/26) and I need to get to the airport by the 5th of May so I need this repair done quickly but I know they're going to drag their heels about it because obviously it's a lot of money for them. It's actually over what they were selling the vehicle for!

Obviously I haven't got the official diagnostic report from the specialist yet, so I'm also hoping the original garage got it wrong and it's an easy fix - if that's the case, I'll probably pay it straight away and then ask the dealership to reimburse me directly - if they drag their heels it's not the end of the world if it only cost me 1000 to repair.

Questions:

What are my options here?

Realistically, am I going to get the money in time for the journeys I need the car for?

How do I even ask for payment to be delivered? Directly to the specialist? Or to my account and then I pay to specialist (which is my assumption)

Realistically, would they even pay it? Would they just try to give me a refund on the car price (even that kinda sucks because I'm out of pocket by about 3k, but it's doable)?

Would the garage be able to weasel out of paying by saying the car (being 14 years old and having 98k miles done) should expect those kinds of repairs by now? (I really hope not because then I'm fucked, and my old car had 115k miles and was 12 years old and did not need engine repairs)