Congratulations. I have a very similar case open against EVRi whereby I sold a watch on eBay and it never arrived. They are claiming that my contract is with Packlink, much as they did in your case. I have read this entire thread and while the legal language and specifics are a little daunting in all honesty, It's very pleasing to see that you were successful with your claim.  Thank you also for posting your WS and bundle which, if my mediation is unsuccessful, will become very useful for me.

My partner has gone ahead and sent the following so I’m hoping it’s worded correctly.    Vehicle registration number:.  Finance agreement –   As you know, the vehicle which I purchased from Doves Horsham on 29/9/23 and partly financed by Santander credit agreement has shown signs of water ingress and body corrosion.   We have raised the matter with Santander finance company who informed us that we would need to establish that the defect was there at the time of purchase.   I can now tell you that the cause of the water ingress was caused by incorrect sealant being used to fit the replacement windscreen and it is obvious that this situation existed at the time of purchase. In any event, I am entitled to purchase a vehicle which is in satisfactory condition and remains that way for a reasonable period of time. Clearly a Mercedes vehicle costing £21,000 should not be allowing water to enter the vehicle and should certainly not be rusting away for many years.   The Mercedes dealership at Croydon have carried out a detailed analysis and I am supplying you with a copy of their report which confirms what I have said above. Furthermore I have obtained a quotation for the full cost of repairs which includes replacement sealant, repair of corrosion, replaced components that were affected and water testing so that the vehicle is returned to the condition that should have been in when it was sold to me.   On this basis I hold you responsible for the cost of repairs which are £3301.48 including a 10% discount (£3653.28 before discount) - As a result of your breach of contract.   I have been without the vehicle for 5 weeks so far and as you can imagine this cannot continue. I require confirmation that you will  be covering all costs incurred to fix this fault.    I look forward to hearing back from you  within 2 days however, given the urgency of the situation and the fact that the vehicle is now ready for collection from Mercedes, a sooner response would be appreciated

Yes in hindsight that would have been the best course of action but due to Mercedes taking 4 weeks with misdiagnosis (which were initially classed as wear and tear - battery & fuses) and then correctly identify the problem we had no choice but to go ahead and agree to works being done.   

SERVICE BY EMAIL Rules 6.3(1)(d) and 6.20(1)(d) of the Civil Procedural Rules (“CPR”) allow service by email of claim forms and other documents; these Rules are supplemented by Practice Direction (“PD”) 6A. In accordance with PD 6A.4, in order for service by email to be valid, the recipient party must have previously indicated in writing to the party serving that they are willing to accept service by electronic means and provided a fax number, email address or other electronic identification to which it must be sent. The PD also requires the sender to ask if there are any restrictions on the size of documents that can be received by email.   .

NO EMAIL. Not only for the reasons outlined above. CPR Rules state that PAPLOC's can't be served by email unless you give them express consent to this (just giving them your email address is *not* express consent), meaning that they have to be served by post. Either way, a court claim can't arrive by email either. The courts will send that by post. They'll file it to your old address and you'll have no idea until a couple months later when all of a sudden a CCJ is on your credit file because they've obtained what we call a backdoor CCJ. In easier terms, stick to proper post for legal/contractual disputes.   In this case, ignore entirely. That is more useful for more "normal" private parking invoices.