I know Oil leaks have been covered before but can't seem to find anything relating to where mine is coming from.
It appears to be from the front cover.

Will taking this off involve re-timing?

Yes you'll need to retime if it is a standard crank without a keyway.

The bottom pulley is friction fit as standard, to refit good practice is new friction washers and crank bolt, circa £25 a cam timing tool here: https://www.toolstoday.co.uk/sealey-petrol-engine-setting-locking-kit-ford-mazda-volvo-1-25-1-4-1-6-1-8-2-0-2-3-16v-duratec-belt-chain-drive?gclid=CMf hpbPjw84CFcky0woduXwDNg

Cheers

Ian

Thanks Ian,

A job I'll save for winter in that case.

Tools ordered in preparation

I is worth trying adding some Engine Oil leak fix and 500ml of mineral first. Fully synthetic oil should have additives in them (plasticisers) to keep the oils seals from becoming dry and brittle and shrinking but not all synthetic oils have plasticiser in the additve package and not all plasticiser additives work with all seal materiels. The aftermarket leak fix additives contain a number of different plasticisers to restore oil seals elasticity ans slighly swell them.