Pros and cons, like you say. The multi-company route is best if these entities are likely to be large enough to justify it. Downsides are that you obviously will have VAT implications. With a single company its straightforward, whereas many diddy companies may not make the threshold for registration and depending on what you do and/or what your intentions are with these businesses could be a good or bad thing from a VAT perspective.
Furthermore, your accountant will charge you for every annual return filing he does, which isnt cheap if youre just setting out and you will have to allocate the shared costs (which online companies tend to have) between the companies and pay them individually, unless you create a parent group company. You cannot transfer funds between individual businesses on an ad hoc basis without incurring a tax liability unless these businesses are all be owned by the same group company. To be able to create a group company, the child companies must have the same share ownership structure, otherwise, like I say, transferring money about between companies and paying for one anothers costs when they arise will be frowned upon by HMRC.
The benefits with having multiple companies is that the user experience can be more wholesome when the name on their statement says Online Dating Company Ltd rather than Stender Media Group Ltd. Also, exit strategies and selling off of assets are a little easier if the companies are individual entities in their own right. There are also some nice tax efficiencies to be gained with a multiple company set up (with parent) and, if you intend going UK Ltd, a parent company gives some nice umbrella protection and piece of mind if things go tango down at the child company level.
If you are not going global from day one and not creating too much financial exposure for yourself, my advice would be set up a single company with the most generic of names you could possibly imagine like "Stender Media Ltd" and trade the websites as if they were real companies simply adding the usual "Stender Media Ltd t/a Online Dating Website" on the invoices and "Online Dating Website is owned by Stender Media Ltd" on the website. Shouldnt go too wrong with that approach.
