Question about nSequence with regard to bip-0112 and bip-0068
So turns out the sender has to set the same number in the nSequence that is in the script. In the case above 10 will be interpreted as 10 blocks because I was using bitcoinJS lib which converts the decimal 10 to a 32 bit integer which would be

00000000000000000000000000001010

according to bip68 https://github.com/bitcoin/bips/blob/master/bip-0068.mediawiki

the last 16 bits is the value i.e. 10 in binary signed twos compliment is
0000000000001010

the first 16 bits represents the flags, so as they are all 0s it means the disable flag is set to off and the type flag is set to off which means the number is interpreted as blocks 

however if I did this

00000000010000000000000000001010

it would be interpreted as time span, i.e. 10 * 512 seconds

for anybody like me who needs to stop thinking in terms of decimal/ints and start using 32 uint and thinking in bits/bitshift operations etc
there's a handy bitcoin-js lib which will convert it for you

https://github.com/bitcoinjs/bip68