Are there any "extended stay" or "multiroom suites" in hotels in England?

In general: Yes, the sort of hotel you're looking for exists in England (arbitrary example, there's a Staybridge Suites in Liverpool), though it doesn't seem there are many in the Portsmouth area in particular. I'd suspect that they're less common in the UK in general, owing to the small overall geographic size of the country. Home is rarely more than a few hours away, which leads to fewer stays extending into the weeks or months category on which many extended stay hotels thrive. But that's just speculation on my part.

One resource that I find very useful when looking for 'Extended Stay' type rooms is the directory at biz-stay.com (link goes to their Southampton/Portsmouth page specifically). In this case, it looks like your only real option is an executive room at the Holiday Inn Portsmouth (which is probably a double room, but likely lacks a kitchenette, in my experience); or looking into AirBNB or other short term apartment rentals.

If you're looking for holiday/vacation accommodation in the UK which includes a kitchen and space for a family, one phrase to search for is "self-catering".

It's not so common for hotels to offer such amenities, but it is certainly possible (for example) to rent a cottage for a few days.

According to the Marriott UK website Residence Inn by Marriott ie Extended Stay Hotels do exist in the UK but not in the Portsmouth area.

If you are currently in the US, I think your best bet would be to contact Marriott to explain your situation.

Travelodge is a chain of hotels in the UK where all four family members can definitely stay in one room. This example is for a Travelodge located in the Portsmouth area. As far as I'm aware Travelodge don't have rooms with a separate sitting area/kitchenette. If such hotel rooms do exist in the UK, which I think Residence Inn by Marriott do cater for, I'm sure you will pay top dollar for one.

Travelodge have a central reservations number where you could enquire:

+44 8719 848484

Yes, many hotels provide for exactly this type of scenario. The three types of things you need to look for are:

• Family rooms: often a king size plus two singles (or in our case a king size, two singles and a pull out bed, as we have 3 kids) Many hotels offer these
• Adjoining rooms: have 2 doors to the corridor, but an interconnecting door. These are very common.
• Suite - most of the better hotels offer suites with multiple bedrooms if required, or some may offer pull out beds or camp beds for children that can be set up in the living room or kitchenette areas in a suite

So is a kitchen important ? Or are multi rooms important ?

I would recommend you use marriott.com as a yardstick to know if such hotels exist in England. I did a quick find for you in London : 2 Rooms 4 Guests and I assumed you'd need a kitchennete and found this in the marriott.com website : http://www.marriott.com/hotels/travel/lonql-grand-residences-by-marriott-mayfair-london/ So yes, I can see such hotels exist in England.

Similar search for Portsmouth returned this hotel : http://www.marriott.com/hotels/travel/pmeha-portsmouth-marriott-hotel/

Most hotels in the UK offer family rooms for up to two adults and (typically) up to two children. It isn't clear from your post whether you specified in your search that the third and fourth guests were children rather than adults - perhaps that's why you didn't get good results?

In many cases a 'family room' will actually be a standard room where the sofa-bed has been folded out and made up as a second double bed. If you'd like a bit more space for spending time in the room during the day, you should be able to fold this bed away and use it as a sofa - either doing it yourselves, or asking the hotel to do it for you. I'd check with the hotel to confirm that this will definitely be possible though.

If you're keen on having separate bedrooms, for example so that you can put the kids to bed in the evening then sit and talk or watch TV without disturbing them, you'd probably prefer the interconnecting rooms option, which doesn't usually seem to be an option on booking websites so would need a call to the hotel to confirm, or to find a hotel offering suites as other answers have suggested. The common term for these here seems to be apartment hotel.