You can buy cartons of formula, but if you have loads of luggage powder is just as easy.
I would go all inc, at 5 months hopefully youd dd will be pretty chilled, and you can have the sort of holiday that you want - it'll probably be the last
Lanzarote - Rubimar aparthotel - b&b, but with apartment so kitchen/sep bedroom, quite basic, but right on a beautiful marina with some amazing restuarants and bars, all very child friendly, walking distance to Playa Blanca.
Princes Yaiza - all inc luxury. In Playa Blanca but walking distance to marina etc.
Tenerife - Los Gigantes Spa and Suite - went here last year, half an hours drive away from Las Americas, small town, amazing hotel, spa, all inclusive, lovely food, all suites so seperate bedroom and living area,
Mare Nostrum resort - going here this year, looks fab, 5* in Los Cristianos, can go half or full board, lots of nice restaurants and things to do near by, 5 pools etc.
Unfortunately not flying from Newcastle as live in Glasgow, but I did post on Blyth thread a while ago.