equity income funds or corporate bond funds, which is best.

Neither.  Research ETFs, plenty of info all over the web on them.

These funds you talk of are run by fund management companies who take a nice slice in costs every year, maybe as much as 5% when you tot up all the man fees, custodian fees, admin charges, then there will be dealing costs and possibly stamp duty to pay.

That cost all adds up and detracts from profits over the years to be a considerable chunk of your hard earned.

what do you think of i shares global high yield bond?

Prefer the ishares corporate bond (SLXX LN)

invests in the top investment graded companies bonds worldwide.

Can't you invest through Hargreaves Lansdown and avoid most of the up front charges?

Yes, and also there is the RDR coming into force from the 1st of Jan to stop payments and trail commissions but... there is still a TER (total expense ratio) that the fund management company will rake in.