hello
the recommended brand of pellets by house rabbit society s'pore & by most bunny lovers will be Oxbow. This brand is consider a healthier choice pellets are high fibre, hay based - alfalfa or timothy.

regarding supa recommended here, it is a recommended feed in the UK but the main ingredient is cereal grains (which is not exactly recommended for buns' diet as it may cause them to be overweight). my understanding is that timothy hay is rare in UK & carry a premium price so it makes biz sense for UK manufacturer to exclude timothy grass as main ingredient. So you may want to factor this ingredient consideration on when deciding on pellet choice.

petshops are selling japanese brand pellets like AB, NPF, etc. that has been discussed to be highly addictive. i have tried NPF on my bun previously & it caused intermittence soft stool & bun to be rather heavy in breathing. But all this turn for the better when i change their diet to oxbow.

there are a lot of pet shops at Serangoon Nth as mentioned by gypsy, you make a trip there to checkout the place. However, i prefer to make my purchases online since my supplies are rather fix (gotta feed 4 bunnies now ) & it saves me time. Online pet suppliers gives good discount & hassle free. They deliver FOC for min. order of $50.

www.ipetsonline.com (shop located at French Road next to Lavender MRT station)
www.petdepot.com.sg (shop located at serangoon way)

If u need any other help or info, u can PM me.