Hi Ellie,
(From a fellow Essex bod now living in Wales), Sarfend-on Sea was my old stomping ground!
Anyway, strings like maple/rosewood boards, active/passive basses, Fender/Gibson is all very personal. For a start I haven't tried Roto's at all, but I know lot's of people swear by them (some indeed paid to swear by them )!
I use Ernie Ball hybrid slinkies stnd gauge because they are not too expensive, they have a nice feel under the fingers (not rough), right tension and they sound good! Mark from Bass Direct gave me a freebie set of R.Cocco nickels when I bought my Vigier there, more expensive (hand made) by a tenner a set and I still prefer the Ernies!
Oh La Bella flats are also very good. Try a few and buy the ones that feel and sound right!
Cheers,
LC