I've seen web services (e.g., companiesmadesimple.com, swiftformations.com, companyformations247.co.uk) that offer to register a company in the UK. Prices start low.
companyformations247.co.uk is linked with Barclays and link their offering with a Barclays business bank account.
companiesmadesimple.com offer to provide a "Registered Office" as London EC1.
Q1. are these cost effective services?
Q2. is defining a registered office in EC1 ethical? helpful to start-ups outside of London?
Q3. what are year 2 costs that these services miss?
Forming a limited company in the UK is very simple, in fact it is possible to "do it yourself" with the appropriate forms. The fastest route is to take a pre-built company that has previously been registered and change it, which is what these online firms generally do.
If you want to take money (and it's generally a good idea...) then having a bank account in the company name is necessary!
The registered office has to be real (not a PO box) and is where legal documents will be served, so you'll want mail to be forwarded quickly. It'll also be where the Revenue and Customs turn up for inspections and suchlike. Company director addresses are also listed on a central registry and you can (now) use the registered office for those.
The registered office doesn't need to be on anything that goes to customers. Those that need it will find it out.
The other obligations that the services miss include filing fees with Companies House, the registration authority, which is £15 annually. You also need to submit accounts each year (and if you don't, it's a £1,500 fine).
There's also a Corporation Tax return that needs to go to Revenue and Customs, and each quarter there's a VAT return that needs to be sent too. For simple companies most UK accountants will prepare all these documents and file them at the right time for a smallish flat fee of a few hundred pounds per year. That's definitely worth the expense as while it's all online and pretty easy to do, it's also easy to get wrong!